When we opened our former shop some 25 years ago, the first "new" merchandise I wanted to bring in (vs. our mostly vintage offerings at the time) were French soaps. I knew how great they were from having spent a small part of my teenage years in Europe, and the too-short time we were in Provence. This amazing industry started in Marseille and spread to other areas of Southern France, with easy access so many pure ingredients such as olive oil and lavender. If you do go to Marseille, be sure to visit one of the soap museums to see how it's made – fascinating.
Why are French soaps so great? First: natural ingredients. No lye or chemicals or weird stuff. No talc, which a lot of commercial manufacturers use as filler (and that's the gunk that sticks on your shower door). Second, they are milled three or four times to make them dense and long-lasting. It's kind of like kneading bread to get out all the bubbles: you end up with a densely-packed product (although you probably wouldn't compress your bread dough like that). Third, they are luxuriously foamy and moisturizing. And so gentle you can use them on your face, on your baby, and as shampoo in a pinch. And they aren't packed in a plastic bottle.
I'm such a snob now. Only my French soaps will do (plus a few very well-made US brands), and I go so far as to bring the tiny sizes (25g, which is less than one ounce) along when we travel... because you never know what kind of yucky soap or weird body wash you might end up with in a hotel or even at your cousin's house. If we're on a trip with multiple stops, I'll bring one soap for each location and just leave it behind. Teeny as they are, they'll suffice for two people for about six days, maybe longer.
Where can you buy them? If you're in France, there will likely be a soap merchant at any outdoor market or weekly farmer's market setup, but you'll find that prices are about the same in the U.S. (save your precious suitcase space for other things). They can be found in nice boutiques everywhere. Of course, I am most loyal to our own former shop – Pomegranate Home & Garden in Bend, Oregon. New owner Marti is continuing the tradition with a full array of lovely French soaps in many sizes and scents. Oh, bonus tip: buy extras so you never run out, and store those extras in your linen closet and suitcase to make everything smell great.
There's nothing like a new bar of French soap!