Before you start

A French tax number, issued after your first declaration
Records of worldwide income for the year
A French bank RIB
Credentials for impots.gouv.fr, once you have a number

Step-by-step

1
Fix the withholding rate on your first payslips
With no French tax history, your employer applies the taux neutre from a published grid based on your salary alone. It ignores your household, your children and any other income. Once you have a tax number you can request a personalised rate through impots.gouv.fr, and you can modulate it when your circumstances change. Do this rather than waiting a year for the reconciliation.
OnlineWho: YouAs soon as you have a tax number
2
Understand that withholding does not replace the declaration
Prélèvement à la source deducts tax from your salary, but the annual declaration in the spring is still mandatory. It reconciles the withholding, applies the household quotient and reliefs, and captures income the withholding never saw.
OnlineWho: YouSpring annually
3
File your first declaration on paper if you have no tax number yet
The online service needs a tax number you do not receive until you have filed once, so the first declaration usually goes on paper to your local tax office. This circularity catches everyone and the office is entirely used to it — ask them directly.
In personWho: You
4
Work out your parts and what the quotient does for your household
A single person counts as one part, a married or PACSed couple as two, with additional half-parts for children. Income is divided by the parts, taxed on the scale and multiplied back. The reduction is substantial for a couple with unequal incomes and for families.
OnlineWho: You
5
Price the taxe foncière into any purchase here, separately from the price
Montpellier's commune rate on built property is among the steepest of France's large cities, well above Paris or Lyon. It falls on owners, not tenants, but it is a recurring annual cost that a mortgage comparison from another country will not have modelled. Ask for the current owner's actual bill before making an offer.
OnlineWho: You
6
Declare every foreign account — the penalty is fixed and it is applied
French tax residents must list all foreign bank accounts, life insurance contracts and digital asset accounts annually, whether or not they generated income. The account people forget is almost always a dormant one at home.
OnlineWho: You

Documents you’ll need

French tax number, once issued
Payslips and the annual employer summary
Records of all foreign income and foreign accounts
RIB for refunds and payments
Marriage or PACS documentation, for household parts

Things most newcomers don’t know

The rate on your first French payslip is a guess, and you can correct it in ten minutes.

With no filing history, prélèvement à la source falls back to the taux neutre — a published grid keyed to salary alone that knows nothing about your spouse, your children or your other income. For a single earner supporting a family it is usually far too high; for two earners it can be too low, storing up a bill. Once you have a tax number you can request a personalised rate online and it applies within a couple of months. Most newcomers never realise the number was provisional.

Source: impots.gouv.fr

France taxes the household, which changes the answer completely depending on who you are.

The quotient familial divides household income by a number of parts before applying the scale — one for a single person, two for a married or PACSed couple, extra half-parts for children. A couple with one high and one low income pays substantially less than two individuals earning the same amounts; a single high earner does comparatively badly. Comparing French tax against a country with individual taxation is meaningless without specifying the household.

Source: impots.gouv.fr

A pied-à-terre on this coast is taxed as a policy instrument, not as an oversight.

Taxe d'habitation was abolished on principal residences but retained on second homes, and communes in pressured housing areas may add a surcharge of up to 60% on the commune's share. Montpellier applies the maximum, and so do many of the Hérault coastal communes where a weekend flat is tempting — precisely because holiday homes there displaced local housing. The surcharge is the point, not a rounding error, and it should be modelled before buying rather than discovered on the autumn bill.

Source: service-public.fr

The taxe foncière here is not comparable to what you paid at home, and it is not comparable to Paris either.

Local property tax rates in France are set commune by commune and the spread between large cities is enormous — Montpellier's rate on built property is roughly double Paris's. Only owners pay it, so tenants can ignore it entirely, but anyone converting a rent-versus-buy calculation from another country will get the wrong answer without it. Ask the seller for the last actual avis de taxe foncière rather than working from a national average.

Source: impots.gouv.fr

Common mistakes to avoid

Accepting the taux neutre on your payslip as though it were your actual tax rate.
Assuming withholding at source removes the obligation to file annually.
Not realising the first declaration goes on paper because you have no tax number yet.
Buying a second home on this coast without modelling the residence-tax surcharge.
Failing to declare a dormant foreign bank account and incurring the fixed per-account penalty.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.

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