Before you start

Registration in the canton
Employment contract
Residence or G permit
An AVS number, issued through your employer

Step-by-step

1
Expect withholding at source if you hold a B or L permit
Cantonal, communal and federal tax are deducted from salary at a scale set by the canton. Nothing further is due at the point of payment.
Via employerWho: Your employer
2
German residents: obtain the residence certificate for your employer
Under Article 15a of the Germany-Switzerland treaty, a certified residence attestation limits the Swiss withholding to 4.5% of gross salary. Germany then taxes the income and credits that 4.5%. Without the certificate the Swiss employer withholds at the full rate and you chase the difference.
Via employerWho: You, with your German tax office
3
German residents: count your non-return days
Cross-border status is lost if you fail to return to your German residence on more than 60 working days in a full calendar year for work reasons. Cross that line and Switzerland taxes the employment income in full. Business travel is the usual cause and nobody counts it until the year is over.
Via employerWho: You
4
French residents: hand your employer the stamped attestation de résidence fiscale
Under the 1983 agreement covering Basel-Stadt, Basel-Landschaft, Bern, Solothurn, Vaud, Valais, Neuchâtel and Jura, you are taxed in France and the Swiss employer withholds nothing. France separately pays Switzerland compensation of 4.5% of the gross wage bill — a state-to-state transfer, not a deduction from you.
Via employerWho: You, with your French tax office
5
Residents: request an ordinary assessment if it pays
Above an income threshold it is compulsory. Below it, you can ask for one to claim real deductions — third pillar, childcare, actual travel and meal costs, mortgage interest — instead of the flat allowances in the withholding scale.
OnlineWho: YouBy 31 March of the following year
6
Use the third pillar and check the new catch-up rule
3a contributions are deductible up to CHF 7,258 for 2026 if you are in an occupational pension scheme. From 2026 you can also buy back missed years for the first time, up to ten years back, provided the current year is already fully funded.
OnlineWho: You

Documents you’ll need

Residence or G permit
Annual salary certificate
AVS number
German residence certificate or French attestation de résidence fiscale for commuters

Things most newcomers don’t know

The German and French cross-border rules are opposites, and Basel is where they meet.

A German resident sees up to 4.5% of gross salary withheld in Switzerland and pays the rest to Germany, which credits the Swiss slice. A French resident sees no Swiss withholding at all and pays France, while France transfers 4.5% of the aggregate wage bill to Switzerland separately. Two colleagues on the same team, different payslips, different filings.

Source: Article 15a Germany-Switzerland treaty; the 1983 France-Switzerland agreement

For German commuters, 60 non-return days is the number that quietly ends the arrangement.

If work prevents you returning to your German home on more than 60 working days in a full year, you stop being a Grenzgänger and Switzerland taxes the employment income outright. Conference travel, secondments and long project stints add up faster than people expect, and the count is done retrospectively when the year has already been lived.

Source: Baden-Württemberg tax administration — Grenzgänger guidance

Living in Riehen is cheaper than living in Basel, and the mechanism is unusual.

The City of Basel levies no communal income tax — the canton takes the whole thing. For Riehen and Bettingen residents the canton takes only 50% as its share, and the commune sets its own rate up to the other 50%. Riehen has not been levying the full half, so its residents pay less overall than city residents on the same income. It is one tram ride and a leafier village.

Source: Canton of Basel-Stadt tax law; Gemeinde Riehen tax information

Basel-Landschaft next door is a genuinely different tax jurisdiction, not a suburb.

Allschwil, Binningen, Münchenstein and Reinach are minutes from the centre and in another canton with its own scale and its own communal multipliers on top. Comparing two flats on rent alone in this city is a mistake worth thousands a year in either direction — model the tax and the health premium before choosing.

Source: Federal Tax Administration — cantonal tax comparison

Common mistakes to avoid

Applying German cross-border tax advice to a French-resident colleague or the reverse.
German commuters not tracking non-return days until the year is already over.
French commuters starting work without the stamped attestation, and having Swiss tax withheld they then have to reclaim.
Comparing Basel-Stadt and Basel-Landschaft addresses on rent without modelling the tax difference.
Missing the 31 March deadline to request an ordinary assessment and losing a year of real deductions.

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