As CM said, the French "red bits" aren't much of a problem. If you have Bottlang, you don't need any other book since all the details are in there.
You do need to do a reasonable "plog" and check on the areas you're likely to want to enter. Look 'em up in Bottlang to find the specifics.
Most of the red is low-level (military jets playing wargames), often "cold" at weekends, and most of it you can get cleared through anyway if you call on the relevant frequency (also in Bottlang).
NEVER call Paris Info. It's not there to provide Info, it's there to yell at dumb British pilots who have the temerity to wake up the controller. Talk to ANYONE else listed on your chart etc - I've found them all most helpful.
And yes, you can fly any track you like (just about) between places/VORs. If you like the reassurance, talk to the relevant Controller, get a squawk (even) and tell them what you want to do.