High fee for matchmaking

A certain matchmaker demands a much higher fee for matchmaking than what is generally accepted. When does he have to let the interested parties know about this? Maybe he has to let them know before he offers the match, so that if the sides do not want to pay him the fee that he demands, they can refuse to hear what that he’s offering, or to agree with him on a lower fee? Or maybe he can let them know at a later stage? If so, when? Before the first date, or maybe even before the match has been concluded successfully? Can the parties refuse to pay because they didn’t agree to the higher fee in advance, at a time, when they could still either back out of using his services, or to negotiate his price down?    

Dear …!

If the matchmaker and the two sides of the match agreed ahead of time that the fee is going to be unusually high, then the matchmaker has a right to demand his pay as agreed. But if they did not make an agreement ahead of time, he has no right demand more than the usual accepted fee for such service.   

You should agree upon all the terms ahead of time, before the actual match starts. That is, before the pair begin going out on dates.  

Shulchan Oruch, section Choshen Mishpat, ch. 264, 331; Ktzot a-Choshen, ibid.