The Butterfly Farm (or La Ferme aux Papillons) is located near Orient Beach on the French side of the Island. It is a small "farm" located at the back of a house. The fairly small area consists of a "forest" of plants and trees of all varieties under a large net. The environment is conducive to breeding and displaying butterflies.
To reach the Butterfly Farm from the Dutch side, follow signs to the Middle Region and Orient Beach. Just before reaching Orient Beach, there is a sign pointing down a small narrow road advertising Bay Side Riding Stables. The sign advertising the Butterfly Farm is actually on the left side of the road. Turn right onto Galion Road. The farm is the first place you come to.
The entry fee was $12 per person - a bit steep. We were shown the "farm" area and had about 10 minutes to wander among the butterflies before the tour. The tour lasts about 15 minutes. It is quite informative. There are a couple of cages that contain several chrysalis. Some butterflies had emerged that morning prior to our arrival. Evidently, they emerge fairly early. You are given a ticket to return at any point during your stay on St. Martin (although I'm not sure why one would want to--once you've experienced it, you've experienced it. Maybe if you were a big fan of butterflies...). There is also a small gift shop with some fairly expensive items. Even though the entry fee was pricey, we enjoyed the visit and tour and were not sorry we went. It would be a GREAT place to take children. Their website is www.thebutterflyfarm.com.