Hi, Benoit. I agree with everything that people have already said about Gethyllis. Here's a little bit of additional information. I think the cultural techniques you'll need to use will vary depending on the climate in your part of France. Gethyllis villosa grows pretty well in 20-cm plastic pots for me here in San Jose, California. But I find that in my climate, I need to keep the pots damp throughout the summer. I give them some water once a week. In my part of California, we receive no rain at all for at least six months of the year, and the air is very dry. If I let the pots completely dry out, the Gethyllis bulbs seem to suffer. I think their roots are active in summer, even if they do not have leaves, and so it hurts them to completely dry out. I use a very lean soil consisting of 50% peat moss, 25% sand, and 25% perlite, amended with a little bit of bulb fertilizer. This seems to help prevent the bulbs rotting in summer, even though they are wet. I do not know how other Gethyllis species would respond to this treatment, but G. villosa is pretty happy. Good luck, Mike San Jose, CA (zone 9, min temp 20F / -7 C)