Do I need a fire extinguisher in my car in France? No you don't, they are merely an optional extra and my advice is don't waste your money.
We advise NOT trying to tackle the flames if your car is on fire, but simply to get as far away from it as possible to a safe distance and call the emergency services.
Buying an extinguisher that isn't much bigger than can of furniture polish and trying to tackle a fire with it is probably quite dangerous.
Is a fire extinguisher required in the car in other European countries?
In what we'd consider to be the main ones like, Belgium, Germany, Portugal and Spain etc then again the answer is no.
Though if you take the road less well travelled, through eastern Europe then in some Baltic countries they have them as a compulsory item. The last I checked they are required if driving in Russia also, though I have no intention of ever driving there.
If you are going to take one then a "dry powder" one is best for a car, motorhome or caravan. See image below.