Staying at Marc's place was great. I just needed a bed near Luxembourg and made my reservation at the last minute. I had a bit of trouble (my fault) receiving internet communication setting a time for picking up the key, but he was waiting at the apartment looking for me -- I really appreciated that. The bed was comfortable and the location was very convenient -- a 10 min walk to RER B. Internet worked. Great coffee-boulangerie down the street. I forgot to bring a towel, and Marc provided one. Marc was very friendly, interesting guy. He knew enough English to communicate the essentials. Would stay there again.