Off the top of my head, I know Augustin Robespierre was staying with the Ricords, though I don't know at what address. Charlotte was back in Paris after having been sent to Arras by her brothers, but I can't recall where she was staying - I can try to look it up, though. As for Saint-Just, I don't know, but one of his biographies probably mentions it... In fact, come to think of it, it might be mentioned in Autour de Robespierre : Le Conventionnel Le Bas. I'll check.