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 on arrival
Available at the airport, in phone shops and in tabacs. Identity verification is required but a passport is enough. A French number in your first hours unlocks bank verification and appointment systems.
In personWho: YouDay 1
2
Move to a no-commitment contract once you have a RIB
French sans engagement tariffs are month-to-month and remarkably cheap for large data. There is little reason to accept a long commitment unless a subsidised handset genuinely justifies it.
OnlineWho: You
3
Check how your tariff treats Monaco specifically
Monaco is not part of the European Union and is not covered by EU roam-like-at-home rules. Some French tariffs include it and some do not. If you commute across that border daily, this is the single most consequential detail in your contract and it is worth confirming in writing before you sign.
OnlineWho: You
4
Check Italy too if you will cross often
Italy is inside the EU roaming area so it is normally covered, but fair-use limits apply to sustained use abroad. If you spend a lot of time in Ventimiglia or over the border generally, read the fair-use terms rather than assuming unlimited use.
OnlineWho: You
5
Order fibre as soon as you have an address
Fibre coverage in Nice is good and cheap. Installation takes one to three weeks and may need a technician. In Vieux-Nice's tall old buildings, what can be installed depends on the building.
OnlineWho: You
6
Keep your number when you switch
Request your RIO code by calling a free shortcode from the line you want to port, then give it to the new operator. Never cancel first — you lose the number.
Mobile appWho: You

Documents you’ll need

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

Things most newcomers don’t know

Monaco is outside EU roaming rules, and a border-hopping phone finds that out expensively.

The roam-like-at-home regime covers EU and EEA states. Monaco is neither, so whether your French tariff includes it depends entirely on the operator and the plan. A phone sitting near the border can also latch onto a Monegasque network without you moving at all. For anyone commuting or living east of Nice, confirming Monaco's treatment in the contract is the most valuable five minutes of the whole process.

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 no-commitment plans cost a fraction of the UK or German equivalent.

Source: Arcep

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

Call the free shortcode from the phone you want to port and you are given a RIO code to hand to the new operator, which handles the switch. Cancelling first loses the number permanently, and very few newcomers know the shortcode exists.

Source: Arcep

Fibre in a Vieux-Nice building depends on the building, not the street.

The old town's tall narrow buildings predate any modern cabling and getting fibre into a specific flat can require the co-ownership to have agreed. Coverage maps show the street as served while the flat is not. Make it a viewing question if your work needs the connection.

Source: community-reported

Common mistakes to avoid

Signing a tariff without checking how it treats Monaco.
Assuming EU roaming rules cover Monaco — they do not.
Signing a long 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 old-town building without checking.

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