Lovejoy, that is not a complete answer at all.
Sam, the thing about hour-building is that you can do it absolutely anywhere. It can be with a flying school or club (FTO really is just another word for a flying school), or on an aircraft you own, or own a share of. You can do it anywhere in the world, doesn't need to be in your home country or even in a JAR country.
The link Lovejoy has given you is a list of registered PPL schools in the UK, which is a good starting point, especially since you are coming from abroad and so don't have the local connections needed to find local flying groups or hour-building syndicates (which do not need to be registered anywhere, so there is no such thing as a "list" of them.)
Another option for you would be to rent an aircraft from your local flying club in France, fly over to the UK, and then base yourself somewhere in the UK for a while - have you considered that?
Alternatively, you can go to the USA, Canada, South Africa or Australia to do your hour-building. You'll get to practice your English in any of these places, and they are all much cheaper than the UK for flying - but you'll need to check whether you'll be able to get the part-time work you want.
If I must flying few hours with an instructor at the beginning, do you think these hours can be used for CPL ?
It can count towards the total time (off the top of my head I think it's 150 hours to start the CPL, 200 hours before it can be issued), but not towards the 100 hours P1 that's needed.
Hope that's helpful,
FFF
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