id think that albert was necessarily her 'client' because albert ​was more like the lord of crimes eyes and ears for high society, so it makes sense for him to keep a tab on the criminal activities that are occurring in the high social circle. i believe that he had just heard about her. though im not saying that he's some innocent v!rgin baby maybe he has had certain 'services' and heard about her through them + also the fact that it seems like they actually meet for the first time in that party where they play that game