Versailles was always an important place as it was the palace of the Kings of France starting with Louis XIV. It wasn't really chosen for many treaties at all though. Just look up treaty of Paris and see how many there are. Off the top of my head the only treaties at Versailles I can remember are ending WW1 and France surrendering in early WW2. Hitler chose the same rail cart and same place to get revenge for the Treaty of Versailles ending WW1.