Petit Robert Bistro, Needham location

With vacation comes time to do more exploring, and to try things that perhaps you've been meaning to. My annual end of the year stay-cation yielded the time to cross off a few restaurants on my list. The first was the Petit Robert Bistro, which has three locations currently, one in Kenmore, one in the South End, and the final, and newest, in Needham just outside the city.
We neglected to call for reservations, mistake on our part, so we elected to sit at the bar. Because of this I was unable to check out the real ambiance of the restaurant itself, though I can say that our bartender was delightful and friendly, and luckily the full menu was served.
We started with Moules Marinieres. Traditionally, this preparation of mussels includes white wine, garlic, onions, creme fraiche, butter and parsley. Sadly, I'm not entirely sure how close to the tradition Petit Robert stuck. The mussels were served in a large bowl, and they were well seasoned and tasty, but there was little to no sauce in the bowl. At the end we found a little puddle of what appeared to be caramelized onions and a little white wine. The portion that was left was quite good, however part of the fun of mussels is dunking bread into a tasty broth and enjoying all of the different flavors. Conceptually- a great dish, executed incredibly poorly.
I selected their Braised Lamb Shank as my main course. This was served with white beans flavored with garlic and some Merguez sausage. The lamb was tender and delicious. It fell off the bone with no effort at all. The beans were creamy and garlicky and felt like a delicious indulgence. The sausage was sparse, but luckily unneeded in the dish. Overall, I was very pleased with my lamb. Ive been eating all different cuts of the animal recently, but had yet to have the shank- I'm glad to have had it in such a nice dish that really brought me back to Paris. Clean flavors and nicely prepared.
J was not so lucky. He elected to have the Steak Frites, and though he was to be given a choice of sauces, he was not prompted for his selection. I believe, through my best guess of taste testing, that he was given a bordelaise sauce for dipping his steak. The only saving grace to this dish were the frites. Fried crispy and lightly salted they were some of those perfect fries that you can only find every so often. The steak however was far from perfect. He had ordered it to be medium, and it was served well past well done. It was tough and chewy and extremely dis pleasurable to eat. I have to say- it was a shame that it was so far overcooked as the seasoning used on it was delightful.
Overall, I am disappointed in Petit Robert. Their concept is strong, and they have delicious recipes seemingly, however it appears that their chefs strong suit, at least that night, is not execution. Mussels need their broth, and steak ought to be served at the correct level of doneness. Perhaps its just that location, but if so, they'll want to work out the kinks pretty fast in this budding culinary town, before they get pushed out.