My friend and I had a great stay at Guillaume's place. It's in an excellent location -right in Le Marais a short walk from many things, but tucked in a nice quiet side street. You pick up the key from a keybox, so I didn't actually meet Guillaume but he was very communicative and helpful when need be. The apartment is huge! There are two full size bedrooms that could comfortably sleep four. It's a fun space with a warm, interesting atmosphere. I recommend staying here!