This is a azuré, Bläuling, blue... butterfly (don't know the English word) *g*
But I don't know the exact species, so I can't tell you the latin name.
When it opens it's wings, they are all blue inside. I think it's a male, but I am not sure. Females often are brown in these species, but as I don't know what exact species this one is, I can't tell for sure.