Lavender in Provence

A quick Google search gave several sites, all of which said that, depending upon the specific part of Provence, lavender blooms from mid-June to mid-July.

I would say you're going at just the right time. As someone who always has three or so Lavendula "Grosso" plants growing in the garden, I really like the look of the plants just as they start blooming. When not all the blossoms are quite open yet (before the bees start visiting) they are compact and upright. When all the blooms are heavy with full bracts, there's a bit more color yes, but a good windy spell (which is likely to occur in France) tends to knock the stems down and wreak havoc with the tidy mounds that once were.

We were in the Luberon this past mid-June and saw lavender fields in bloom.

We've been in France twice in that period and lots of lavender. Lots of bees too. Just don't make my mistake and pack it in the same suitcase as your chocolates