If the phone is sold with a subscription, by French law, the operator has to provide a free unlock code after 6 months of subscription.
If you want the unlock code beforehand, you can either pay them a supplement of 100 € or break it yourself over internet (probably about 10 €...).
If the phone is sold unlocked, then there is no limit on the phone, otherwise the operator would be breaking the law, as a subsidised phone is only available with a subscription, and this is considered a "linked sale", which is illegal in france if you do not supply an unlinked option.
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locked and unlocked
If the phone is sold with a subscription, by French law, the operator has to provide a free unlock code after 6 months of subscription.
If you want the unlock code beforehand, you can either pay them a supplement of 100 € or break it yourself over internet (probably about 10 €...).
If the phone is sold unlocked, then there is no limit on the phone, otherwise the operator would be breaking the law, as a subsidised phone is only available with a subscription, and this is considered a "linked sale", which is illegal in france if you do not supply an unlinked option.