Before you start

Passport, for a prepaid SIM
A French RIB, for most contract tariffs
An unlocked or eSIM-capable handset
A French address, for fibre installation

Step-by-step

1
Buy a prepaid SIM on your passport the day you arrive
Available in phone shops and in tabacs. Identity verification is required but a passport satisfies it. A French number in your first hours unlocks bank verification codes and appointment systems that will otherwise block you.
In personWho: YouDay 1
2
Move to a sans engagement contract once you have a RIB
French no-commitment tariffs are month-to-month and remarkably cheap for large data allowances. There is little reason to take a long commitment unless a subsidised handset genuinely justifies it, and it usually does not.
OnlineWho: You
3
Choose the operator on mountain coverage, not on city coverage
Every network works in the valley. They differ substantially in the massifs, in the side valleys and behind ridgelines, and the operator with the best urban score is not necessarily the one that works where you will be walking or skiing. Compare the regulator's coverage maps for the specific valleys you will use before committing.
OnlineWho: You
4
Order fibre as soon as you have an address
Coverage across the métropole is extensive and prices are low. Installation usually takes one to three weeks and may require a technician visit and access to the building's riser.
OnlineWho: You
5
Ask about the building's fibre at the viewing
The older stock in the hypercentre and in Saint-Laurent depends on what the copropriété has agreed to have installed. Operator coverage checkers work at street level, so the street can be served while a specific flat is not. If you work from home, make it a viewing question rather than an after-signature problem.
OnlineWho: You
6
Keep your number when you switch operators
Request your RIO code by calling 3179 free of charge from the line you want to port, then hand it to the new operator, which runs the switch and terminates the old contract automatically. Never cancel first — you lose the number permanently.
Mobile appWho: You

Documents you’ll need

Passport, for prepaid registration
French RIB, for a contract
Justificatif de domicile, for fibre installation

Things most newcomers don’t know

Pick your operator for where you spend Saturday, not where you spend Tuesday.

Urban coverage in the Grenoble basin is strong on every network and tells you nothing useful. The differences appear in the Vercors, the Chartreuse, the Belledonne and the side valleys, where a ridge between you and the mast is decisive and the operators are not equivalent. Given how much of life here happens up there — and that a phone is part of your safety margin on a mountain — this is a rare case where the coverage map should actually drive the choice.

Source: Arcep

French mobile is cheap in a way that surprises almost every arrival.

The entry of a disruptive fourth operator in 2012 triggered a price war whose effects never reversed, and France now has some of the lowest mobile tariffs in western Europe. Large-data plans with no commitment cost a fraction of the UK, Irish or German equivalent. Anyone paying a high monthly mobile bill in France has simply not looked at what is available.

Source: Arcep

The RIO code is how you keep your number, and you request it from the line itself.

Call 3179 free of charge from the phone you want to port and a voice server reads you a RIO code and sends it by SMS. Give that to the new operator; they execute the switch and close the old contract automatically. Cancelling the old service first loses the number for good, and very few newcomers know the number exists — it is the most common self-inflicted telecom mistake in France.

Source: Arcep

Copper is being switched off nationally, so 'the ADSL works fine' is a temporary answer.

France is decommissioning its copper telephone network area by area on a published schedule, with fibre as the replacement. In a well-served métropole this is mostly invisible, but if you take an older flat or a place up a side valley on a copper line, the relevant question is when that exchange is scheduled for closure and whether fibre has reached the building. Ask the landlord what is actually installed.

Source: Arcep

Common mistakes to avoid

Choosing a network on urban benchmarks and finding it useless in the massif you ski in.
Signing a two-year commitment when no-commitment tariffs are cheap and switchable.
Cancelling your old service before requesting the RIO code and losing the number.
Assuming fibre is available in an older building because the street is covered.
Accepting a copper connection without asking when the exchange is scheduled to close.

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