Brookesia minima is considered the smallest described chameleon species. They are from Nosy Be but there are a number of extremely similar species which vary very little in size and morphology. One of these species, Brookesia tuberculata, is from Montagne d'Ambre but over the years there has been a lot of confusion about which species occurs where. As a result, a lot of people think the animals they are seeing in Montagne d'Ambre or other areas are actually B. minima when they aren't.
None of the species from the B. minima complex are exported legally from Madagascar, however. As Justin said, only four species of Brookesia have export quotas and they are very limited.
Chris