You moved in last week and have no idea who else holds a key. Or the old lock sticks, or the landlord only gave you one copy. Whatever the reason, changing a lock is quick, and choosing the right one matters more than most people think.
A French door lock has two parts. The cylinder is the small barrel where the key goes in. The lock body sits inside the door and holds the bolts. Very often only the cylinder needs replacing: it takes a few minutes, the door stays as it is, and the cost is modest. You change the whole lock when the body is damaged, when the door has a poor old mechanism, or when you want real protection.
You will see A2P stamped on better cylinders and locks, with one, two or three stars. It is a French certification that rates how long a lock resists attack. One star is a decent basic level. Two stars suit most flats. Three stars is for places where the risk is higher. Insurers in France often ask for a certified lock, so check your policy before you buy.
A 3-point lock shoots bolts into the door frame at the top, the middle and the bottom. The door cannot be levered at one corner the way an ordinary one can. It is the usual answer for a ground-floor flat or a door that gets a lot of use. A 3-point lock should not be picked at random. We look at your door, then offer two models, not ten, and explain why we think one fits better.
If you rent, check your lease and speak to the landlord. Often the tenant can change the cylinder but must keep the old one or hand over a key. We can give you an invoice that spells out what was done. Keep it with the lease.
A cylinder that is too long or too short is a weakness, since a long one sticks out and can be snapped. We measure rather than guess. And please never accept a lock with no brand and no invoice, however low the price.
For doors that need more than a new lock, read about armoured doors and reinforcement. If you are stuck outside right now, start here. Back to the English home page.