I appreciate janbb’s confident referral, but I have to say that amateur-level classes are not nearly as popular in France as they are in America. With pastry shops on every corner, few home cooks are motivated to attempt anything more challenging than the occasional apple tart. The only option I personally know of for the amateur enthusiast would be the Saturday workshops the Cordon Bleu offers.
If you’re looking for advanced courses, the Ecole LenĂ´tre operates the best in professional level classes. They tend to be focused on specific aspects of pastry rather than general overviews, and will presume a mastery of pastry basics. It’s also inconveniently located in an outlying suburb. But the instructors are among the best in the world.