Accountant Engagement Letter: What to Check Before Signing

Quick answer. An engagement letter is a mandatory written contract before any accountant intervention, established under Ordinance n° 45-2138 (19 September 1945) and the Code of Ethics (Decree n° 2012-432, 30 March 2012). It must specify: identification of parties, exact nature and scope of services, fees and payment terms, duration and renewal conditions, professional liability and insurance, and termination clauses.

In 2026, the regulatory framework governing accountants has tightened. Document retention disputes and scope conflicts have prompted stricter contractual clarity enforcement. E-invoicing mandates (September 2026), intensified automated tax audits, and multiplying compliance standards (CSRD, payroll norms, VAT…) make it critical that both parties understand exactly who performs what work, at what cost, and with which responsibilities.

A written engagement letter protects both sides. The client knows what services are included and avoids surprise invoices or document holdups. The firm demonstrates professionalism and has legal cover in disputes.

Ordinance n° 45-2138 (19 September 1945), the founding text of the profession, requires accountants to operate under deontological principles. Decree n° 2012-432 (30 March 2012) is more explicit: it requires accountants to formalize terms in writing before beginning work. Article 151 of Decree No. 2012-432 expressly requires a written contract detailing the nature and extent of the engagement.

This is a legal obligation, not optional. Any firm asking you to start without a signed engagement letter fails a fundamental professional duty.

The National Council of Chartered Accountants (CSOEC) has issued professional standards specifying minimum engagement letter content, reflecting best practices of credible firms.

Clear Identification of Both Parties#

The letter identifies: the firm (name, registration number, address, SIRET), the client (company name, status, address, SIREN), and the authorized signatory.

Exact Nature and Scope of Services#

This is critical. The letter must specify precisely what the accountant covers:

Core services: bookkeeping, review, financial statements, tax filings (corporate tax, VAT, payroll returns).

Optional services: tax planning, financial dashboards, audit support, succession planning.

Explicit exclusions: employment law, general legal counsel, litigation, external audit.

For multi-entity groups, scope must be explicit: does the firm cover parent, subsidiary, or both?

Fees and Payment Terms#

2026 market note: Accounting fees are unregulated. Market range: EUR 150 to EUR 2,000+ monthly. Obtaining multiple quotes is standard due diligence.

Duration and Renewal Terms#

Mutual Obligations#

Firm: confidentiality, professional due diligence, delivery deadlines, notification of material changes, professional liability insurance.

Client: timely supply of documents, honest declaration of income, notification of status changes, payment on schedule.

Professional Liability and Insurance#

The letter must address: scope of liability (standard professional diligence), potential liability cap, existence and amount of RCP insurance, exclusions from liability for advice outside scope.

Document Access and File Handover#

Access: Who retains original documents? Who accesses bank statements and tax filings?

Handover on termination: The firm must transfer the complete file to the successor within a defined timeframe (ideally 15 days). The Code of Ethics requires this, with no right of retention.

Termination Clauses#

The letter must provide: client termination notice (typically 3 months), firm termination notice and grounds, effects of termination (fees owed, file transfer).

Confidentiality and Professional Privilege#

The letter reiterates professional secrecy and clarifies: who within the firm accesses data, how data is handled under GDPR, commercial use of anonymized data?

Sole proprietors/micro-businesses: the engagement letter remains mandatory. It clarifies whether VAT compliance or social contributions are in scope.

Multi-member structures: the letter clarifies who signs and who receives reports.

Startup founders: it can distinguish pre-launch advisory from ongoing bookkeeping.

Full-service firms: it clarifies which department covers what and whether liability differs by service line.

• E-invoicing mandate (September 2026): confirm the letter covers reception and processing. Some firms charge extra.
• Cybersecurity: the letter should detail security measures and whether cyber insurance supplements standard liability.
• CSRD and ESG reporting: if you trigger mandatory reporting, does the engagement cover it? At what cost?
• Annual fee reviews: in an inflationary environment, check the fee formula clearly.

Recently a mid-sized manufacturing firm contacted us after switching accountants. The former firm held documents for 18 months, claiming undefined outstanding fees. No engagement letter specified file return procedures. After intervention by the professional institute, files were released—but six months were lost to arbitration.

A startup that raised venture capital had an engagement letter mentioning only bookkeeping. The firm invoiced separately for treasury adjustments the client assumed were included. Without defined scope, USD 15,000+ in disputed fees arose.

These situations stem not from malice but from vagueness or outdated letters never revised as the engagement evolved.

Hayot Expertise perspective. Before signing, dedicate 30 minutes to carefully read the letter. Ask six key questions: (1) What is the monthly and annual cost? (2) What exactly is in scope? (3) How long to receive documents after year-end? (4) What is excluded? (5) How do I terminate? (6) How is my risk covered by the firm's insurance?

If any answer is unclear, request a written amendment before signing. Upon firm change, demand written confirmation of document transfer—it's your legal right.