Deposit invoices with Claude: start from the agreed amount

Prepare a deposit invoice with Claude →

An architecture firm has just signed a project-management contract for the extension of a single-family house. The contract sets a 15% deposit at signature, but when it comes to invoicing, the architect hesitates between the percentage actually negotiated and a different default rate suggested by a template found online. Should VAT be calculated on the whole contract or only on the deposit? What should be done if the client has not yet paid anything when the document is issued?

A deposit invoice is the first accounting document of an architect's commission, issued after the contract or fee proposal is signed — not merely a promise of future billing. A mistake at this stage — an invented percentage, a missing mention, confusing the deposit requested with the deposit received — carries through every later invoice of the commission, all the way to the final invoice that closes it.

This article details what sets a deposit invoice apart from a simple request for funds, the mentions that make it compliant, the method for calculating its amount from the signed contract, and the situations where it is not enough on its own.

Summary

1. A deposit invoice, not a simple request for funds
2. Mandatory mentions on an architect's deposit invoice
3. Calculating the deposit amount without errors
4. Building a deposit invoice step by step
5. When a deposit invoice is not enough
6. What we observe among independent architects
7. Training to make invoicing more reliable
8. Frequently asked questions

A deposit invoice, not a simple request for funds

A deposit invoiced by an architect is not an informal notice of a future payment: it is a full accounting document in its own right, with its own mandatory mentions, distinct both from the fee proposal that preceded it and the final invoice that will close the commission. Confusing it with a simple request for funds — or with the payment itself — is the most frequent source of error in an otherwise correct invoicing record.

An accounting document, not a promise

An informal request for funds simply announces a future amount; it has no accounting value and does not by itself trigger any tax obligation. A deposit invoice, by contrast, records a payment right acquired as of its issue date: it must be recorded in the accounts and declared as collected VAT, whether or not the client has already paid. Issuing a "request for funds" that in fact carries every mention of an invoice, without calling it one, avoids none of these obligations: it is the substance of the document, not its title, that determines its treatment.

What the signed contract or proposal must confirm

The deposit percentage, like an architect's fees as a whole, is not set by any official schedule: it results from free negotiation between the architect and the client, as the French Ordre des architectes points out. Before issuing the invoice, it is therefore necessary to re-read the accepted contract or proposal to check three points: the percentage actually agreed, the event that triggers billing, and whether the reference amount is stated excluding or including tax. A document template that offers a default rate never replaces what was actually signed with the client.

Mandatory mentions on an architect's deposit invoice

An architect's deposit invoice carries the same mandatory mentions as any service invoice, supplemented with information specific to a regulated profession. Omitting one of them does not cancel the debt itself, but exposes the issuer to an administrative penalty and deprives the client of information they are entitled to expect from a professional. A general summary of these rules appears on the Service Public Entreprendre page dedicated to mandatory invoice mentions (French source).

Identity, VAT and numbering

Article L441-9 of the French Commercial Code requires the full identity of the issuer and the client, the issue date, a precise description of the invoiced service and its unit price excluding tax. For an architect, this is supplemented by the registration number with the Ordre des architectes and the reference of the ten-year (décennale) insurance taken out under Article L241-1 of the French Insurance Code, as detailed in the Ordre des architectes' fee-invoicing sheet. VAT on the intellectual services of a VAT-liable architect is 20%, calculated on the amount excluding tax under Article 278 of the French General Tax Code. An architect under the VAT exemption scheme (franchise en base) charges no VAT at all and must instead carry the mention "TVA non applicable, article 293 B du CGI", set out in Article 293 B of the same code: in that case, a tax-inclusive amount must never be calculated. Numbering, finally, must follow a continuous chronological sequence kept in the architect's own accounts, never the default sequence proposed by a document template.

Mentions that apply only between businesses

Article L441-9 also requires stating the late-payment penalty rate and the flat-rate €40 indemnity for recovery costs, whose amount is set by Article D441-5 of the French Commercial Code. Both mentions apply only to business-to-business relationships: a deposit invoice addressed to an individual building their own home does not need to carry them, while an invoice addressed to a developer, a company or a co-ownership body acting for its own professional activity must include them. Confusing the two regimes means either omitting a mandatory mention, or applying a clause to an individual that does not concern them.

Calculating the deposit amount without errors

The amount of a deposit invoice is calculated from two verified figures, never assumed ones: the percentage actually agreed, and the tax-excluded base it applies to. The most common mistake is applying that percentage to an amount that includes an option the client did not select, or confusing the tax-excluded amount with the tax-inclusive one.

Starting from the agreed percentage, not a default value

Fictional example: a project-management contract sets a flat fee of €12,000 excluding tax and a 15% deposit at signature. The deposit to invoice is therefore €1,800 excluding tax, or €2,160 including tax once 20% VAT is applied. A template that suggested a default 30% deposit would lead here to invoicing €3,600 excluding tax — an amount nothing in the signed contract justifies, and which should be corrected before the invoice is issued.

Identifying the event that triggers billing

The contract or proposal generally states the moment when the deposit becomes due. That moment also determines which documents must be gathered before invoicing, and the most frequent risk attached to it.

Building a deposit invoice step by step

Building a reliable deposit invoice takes five steps, always in the same order: they prevent discovering after issue that a document was missing or that an amount did not match what was signed.

Step 1: Gather the accepted contract or proposal. The reference document contains the deposit percentage, the event that triggers it and the chosen calculation base. Without it, none of the following steps rest on a verifiable foundation.

Step 2: Check the applicable VAT treatment. An architect liable for the 20% rate, or under the VAT exemption scheme with the mention "TVA non applicable, article 293 B du CGI": the two regimes produce neither the same calculation nor the same mentions on the final document.

Step 3: Calculate the tax-excluded amount, then the tax-inclusive one. The deposit's tax-excluded amount is derived from the agreed percentage applied to the agreed base; the tax-inclusive amount, where applicable, is obtained by multiplying that amount by 1.20, rounded to the nearest cent.

Step 4: Number the invoice and link it to the contract. The contract or proposal reference must appear on the deposit invoice, so that the progress and final invoices that follow can be tied to it unambiguously.

Step 5: Issue the invoice and track collection separately. Generating the document proves neither that it was sent nor that it was paid: the invoice reference and the proof of payment must be kept as two distinct pieces of information, so the same deposit is never deducted twice later on.

When a deposit invoice is not enough

A properly built deposit invoice does not resolve every situation. Some commissions require checks that go beyond what even a complete document template can cover on its own.

A commission involving several clients — a co-ownership body, a self-build collective — often implies several distinct deposits, one per identified co-contracting party, with an allocation best reviewed by a legal professional before issue. A contract setting several staggered deposits across the early phases of the commission requires checking, before each issue, that an earlier deposit has not already covered the same tranche: the risk of double billing grows with the number of instalments. Finally, if the client disputes the deposit itself or refuses to pay the invoice issued, the answer is not a new invoice but a documented reminder, whose wording follows rules of its own, distinct from those of a deposit invoice. A draft invoice prepared with the help of an AI remains, in every case, a draft: it must be reviewed and approved before issue, and by a legal or accounting professional as soon as the situation departs from a standard case.

What we observe among independent architects

In our exchanges with independent architects about their invoicing, the sticking point is almost never the deposit calculation itself: an architect knows the negotiated percentage and can multiply an amount by a VAT rate. What costs time is reformatting the document for every new commission — retrieving the signed contract to check a percentage, adapting a template built for a lump-sum fee to a commission billed by phase, or simply remembering whether the previous invoice number really was the last one used. That is repetitive, low-value work, not a lack of skill — and it is exactly the kind of task a well-built document template removes, without taking away any of the professional judgment on the amount and timing of billing, which remains entirely in the architect's hands.

Training to make invoicing more reliable

Setting up a deposit-invoice template once and for all is not enough: it also needs to be kept alive from one contract to the next without losing time on every commission. For an architect practising as a self-employed professional (NAF code 7111Z in France), the FIFPL fund covers part of the cost of Qualiopi-certified training under 2026 criteria set at €300 per day and €900 per year, with e-learning capped at 50% of the daily rate. This funding must be arranged before training starts, not after.

Frequently asked questions

Can a deposit invoice be issued without a signed contract or proposal?

No, or at least not without risk: a deposit invoice records the execution of an agreement already concluded, it cannot substitute for one. Issuing a deposit before the contract or proposal is signed amounts to invoicing a service whose scope and price are not yet fixed in a binding way, which exposes the architect to having to cancel or correct the document if the client is still negotiating terms. Good practice is to wait for signature — or, failing that, an explicit written agreement on the amount and purpose of the deposit — before issuing the invoice.

What deposit percentage can an architect ask for?

There is no rate imposed by law or by an official schedule: an architect's fees, including the portion requested as a deposit, are freely negotiated with the client, as the Ordre des architectes points out. The percentage varies significantly from one architect to another and from one commission type to another, with no reference threshold: only the percentage actually written into the signed contract or proposal should serve as the basis for the calculation. In practice, that percentage must always be traceable in writing to the accepted proposal or contract, otherwise a document template can only fall back on a default rate that matches no real agreement with that client.

How is VAT calculated on an architect's deposit invoice?

A VAT-liable architect applies a 20% VAT rate to the tax-excluded amount of the deposit, in accordance with Article 278 of the French General Tax Code; the tax-inclusive amount is obtained by multiplying that tax-excluded amount by 1.20, rounded to the nearest cent. An architect under the VAT exemption scheme charges no VAT at all and must instead carry the mention "TVA non applicable, article 293 B du CGI" on the document, never showing a tax-inclusive amount distinct from the tax-excluded one. The applicable regime — VAT-liable or exempt — must be checked before every issue rather than assumed identical from one commission to the next, particularly for an architect whose annual turnover changes from year to year.

What should be done if the client does not pay the invoiced deposit?

The deposit invoice remains due even without payment: it must be kept as issued, with its due date, neither cancelled nor replaced as long as the commission has not been discontinued by agreement of both parties. If the agreed payment period is exceeded, the appropriate step is a documented reminder — a friendly one first, then possibly a formal notice — whose wording and content follow specific rules distinct from those of the invoice itself. Issuing a new invoice for the same deposit, or changing its amount after the fact, would create an inconsistency in the commission's accounting record.

Must a deposit invoice mention late-payment penalties and the recovery-cost indemnity?

Only if the client is a professional acting for their business activity: in that case, the late-payment penalty rate and the flat-rate €40 indemnity for recovery costs, set by Article D441-5 of the French Commercial Code, must appear on the invoice. When the client is an individual building or renovating their own home, these two mentions do not apply and should not be copied as-is from a template built for a business-to-business relationship. Adding these mentions by default to an invoice addressed to an individual is not merely pointless: it applies a clause that does not concern them, risking undermining the document's credibility if a later disagreement arises.

A reliable deposit invoice rests on three elements that do not change from one contract to the next: a percentage and a triggering event drawn from the signed document — never from a default template —, the full mandatory mentions depending on whether the client is a professional or an individual, and a tracking process that always separates the invoice issued from the payment received. Once that foundation is in place, it is exactly what the deposit-invoice generator applies automatically, VAT calculation included, while leaving the architect the decision on the percentage and the timing of billing.

For the rest of the commission, our method for the progress invoice details how to invoice progress without ever re-billing a deposit already issued, and our architect fee-proposal guide revisits the document that precedes and grounds the deposit.

Training 100% fundable via OPCO/FIFPL. Qualiopi-certified programme. To structure your invoicing (proposal, deposits, progress invoices, final balance) with AI as part of our AI for architectural management training, contact Educasium and specify your status (employee, self-employed, business owner) and your goal.