We had a great stay at Helene's place. The appartment is situated in a perfectly safe building. The neighbouhood is great between La Republique and Le Marais. A lot of cute shops and good places to eat in walking distance. We really liked the Marche des Enfant Rouges.
We stayed with 3 persons, the third slept on the couch wich was not comfortable. For 2 nights it was ok.
We were even allowed to check out later on our last day which was really nice! Would recommend this place if you like to stay in a quiet area with lots of Nice places close by. Also a really good Connection with public transport.