The way I understand it, the French Mint often works with private companies to release their new issues with small mintages (the Renault racing car company, the owners of the rights of Hello Kitty, etc.). These companies often own the majority of the coins issued. I believe that the Mint itself only has a portion of these coins to offer on their web site. The 2006 Queen Amelie of Portugal (mintage of 3000) was sold out a few days after it went on sale.