My accountant once told me: "The clients I lose are not those who go bankrupt. They are those who go bankrupt because of mistakes I could have avoided if I had seen them earlier." He was right. Most accounting problems for small businesses are not technical — they are behavioral.
Mistake 1: Mixing personal and business accounts
This is the number 1 mistake by frequency. The business owner uses their personal card to pay a supplier, deposits a client check into their personal account, makes a transfer between the two accounts without documentation.
Result: When it comes time for the balance sheet, the accountant spends hours untangling the transactions. VAT is miscalculated. The tax authority, in case of an audit, reclassifies the movements as personal withdrawals and issues a correction notice.
The solution: a dedicated business bank account from day 1. All business expenses go through this account, all income too. If you advance a personal expense, file an expense report properly.
Mistake 2: Not setting aside social security contributions
In a micro-enterprise, it's simple: charges are proportional to revenue, you pay them as you go. But in a company (SARL, SAS), the director's social security contributions are called with a one-year delay, based on N-1 income.
Concretely: your first year, you pay a minimum flat rate (around 1,100 euros). The second year, URSSAF regularizes based on your actual income. If you paid yourself 40,000 euros in the first year, the regularization can reach 15,000 euros all at once.
The solution: set aside 40 to 45% of your director salary each month into a dedicated savings account. When the regularization call arrives, the money is there.
Mistake 3: Forgetting collected VAT
You invoice 1,200 euros including VAT. Your client pays you 1,200 euros. You spend 1,200 euros. Problem: 200 euros of this 1,200 do not belong to you — it's the VAT you must remit to the State.
It's the classic trap: spending VAT money without realizing it. When it comes time to file, you have to find the money and it's no longer there.
The solution: when you receive a payment, transfer the VAT amount (16.7% of the total for a 20% rate) to a separate account. Never touch this money.
Mistake 4: Filing your receipts once a year
"Everything will be given to the accountant in January." The sentence that makes all accountants cringe. Because in January, you're missing half your invoices, you don't remember what a certain debit represents, and the accountant has to guess.
The solution: scan or photograph each receipt the same day (apps like Dext, Pennylane or Indy do it in 10 seconds). File by month. Send to your accountant at least each quarter.
Mistake 5: Not distinguishing between profit and cash flow
"15,000 euros of accounting profit, but no money in the account." It's perfectly possible and it happens all the time. Accounting profit includes invoices issued but not yet collected, charges recorded but not yet paid, depreciation that corresponds to no cash movement.
The solution: track your profit separately (with your accountant) and your cash flow (with your bank statement and cash flow forecast). These are two different pieces of information and both are necessary.
Mistake 6: Choosing your accountant by price
An accountant at 80 euros a month who only does data entry and the balance sheet is a risk. An accountant at 200 euros a month who alerts you about your cash flow, optimizes your compensation and supports you in your decisions is an investment.
The solution: choose an accountant who understands small businesses (not a firm that mainly handles medium-sized companies with 50 employees), who is responsive, and who plays an advisory role, not just a technical one.
Accounting is not a necessary evil. It's a management tool. Entrepreneurs who succeed are those who look at their numbers each month.