Guillaume's place was very cozy and a great place to spend several days while in Paris. It's a block down from the Metro, so getting around town was a breeze (~half hour to center of town). Some nice details: He sent me directions from the airport to the apartment before my arrival and there was a bottle of wine on the table when I got there. The kitchen is decently stocked, so I was able to cook some. The neighbors are quiet.
It was a nice home away from home!