Absynthe, which the sign says is legal throughout Europe and OK in the US for personal consumption, along with "Real Cannibis Tincture, ~great effect~, Marihuana extracted in Vodka" The sign also says it's available for export with a label that doesn't have unnecessary information (ie doesn't mention the cannibis part, I'm guessing.)
What an ironical advert with poor Vincent on it. It almost says: "drink Absynthe and you'll snap like he did". Oh yeah, I hope you went to Van Gogh museum, it's one of the most amazing experiences I've had.