The lower speed limit came in 1st July last year in France and, so far. only four main cities require a clean air sticker. They're not expensive (a few euro's) but do need to be bought in advance, they are only required if you plan to visit the city centres, not the best use of two wheel time anywhere and certainly not in a country like France with thousands of miles of glorious, quiet roads.
I've been over three times on a bike since the lower limit came in, no problem, same as riding here in the UK, if you're reasonable, keep your eyes open and don't ride like a loon then you'll be fine. If you fancy a blast then it's still eminently possible just you risk a fine, same as here. It hasn't suddenly become a police state so and no one should let headlines put them off enjoying what still is a wonderful country for riding a bike and one so easy to access for us here in the South.
Careful with the hi viz though as you may find yourself manning a barricade ; )
Have fun!
