The location was absolutely perfect. St. Germain was a perfect spot for our first time in Paris and we could not have asked for a better backdrop. It also didn't hurt that it was literally a few steps away from a great restaurant (L'avant Comptoir). We found it extremely accessible to the Seine River for sightseeing, Notre Dame Cathedral, and other points of interest for tourists.
The bath (downstairs) and toilet rooms (upstairs) are segregated, however, we did not find that to be a hindrance at all.
The front door is a little tricky to open at first, but Bertrand guided us through it. (Fyi, it's not complicated at all).