Trying to plan my trip to france, how should i plan my route? which month is best to visit for these places?

i want to start in paris and want to visit provence (including seeing the lavendar fields), and annecy, and also mont blanc. is it best to rent a car to visit all these places or is the rail system sufficient?

Rent a car, you'll be more free (even if speedways and gazeline are expensive), little town aren't served by train and to go from a region to another, you often need to come to Paris, changing the station..., and trains are busy during the weekends.

For your visit, lavendar fields are beautiful in the begining of summer (end of June, begining of July, then, it's too late). During summer, people who live in Paris are in vacation, weather is great, it could be great on July, 14th (even if the military procession isn't very interesting, fireworks are famous). Alps are great in each season. For a one month trip (July), I would advice you to go to Paris but not for a long time, maybe 1 week, then 1 week in Provence (then it's very busy), go back to Paris for the National Day and go to visit Alps (Annecy is a little town, the lake is great but you don't need much time to visit it). Go then to Chamonix (Mont Blanc) and eventually a few days in Provence to go to the sea (very busy but very warm during late July). In general, France have a good weather during this period.

I live in France (sorry for my langage!!! ). Best choice is to rent a car...; And buy a good map !!!!
To visit these places the railways is too much complicate...

the lavendar fields are green at spring, blue at summer and silver at autumn....

mont blanc is really beautifull at spring...(mai and june)

Have a nice trip !!!

You can use train. Trains go everywhere (not on Mont Blanc of course).