Who are the people we see in the Merovingian's restaurant/club?

We don't know much about these characters so we don't know for sure, but we can make educated guesses.

The character we know most about from the Le Vrai restaurant is the beautiful woman who was given a cake by the Merovingian which gave her an orgasm. Through dialogue between the Merovingian and Persephone we learn that this woman later met the Merovingian in the bathroom for a sexual encounter. Given the fact that the Merovingian did her a favor (by giving her that cake) it's not likely that she was at the restaurant because she's an Exile either already working for him or hoping to gain an audience with him for the first time in order to receive his protection -- if she was an Exile she'd already be in the Merovingian's debt and/or in need of his help so he wouldn't have needed to seduce her with the cake. Based on what we know, therefore, it seems most likely that this woman is merely a bluepill. If she's a bluepill who did not already know the Merovingian then the existence of Le Vrai is likely public knowledge, and most of the other restaurant patrons are probably bluepills as well.

Club Hel is a different story. To enter Club Hel you have to (1) get past the gun-toting bouncers guarding the elevator to Hel, (2) know to press the red "Help" elevator button with the "p" scratched off, and (3) get past the coat check area filled with gun-toting guard programs who can defy gravity. Hel is not only under much heavier guard than Le Vrai (the entrance of which is really only "guarded" by the maitre d'), but to enter it requires some hidden knowledge. Additionally, there are many more armed guards within the club itself compared to within Le Vrai (albeit the Merovingian did have some powerful bodyguards in Le Vrai, such as the Twins). The Merovingian clearly does not want untrusted people or programs entering Club Hel so it's very unlikely that a bluepill would discover this club and find a way to access it without some sort of interaction with one of the Merovingian's henchmen. It is possible that some bluepills were given access either as hired employees (e.g. perhaps the coat check girl who puts up no resistance) or as a reward for doing something for the Merovingian, but if so they probably did not know the true nature of what they were doing. The majority of patrons of Club Hel are therefore likely to be Exiles.

Given the differences between Le Vrai and Club Hel, it seems that Le Vrai is a more public place where programs and people can have an initial meeting with the Merovingian, and Club Hel is a more private place where the Merovingian can have more important meetings with more trusted henchmen.