Actors

The Notaire: public official qualified to validate a sale by a legal act and to register it officially.

The Mortgage Broker : acts as an intermediary between  lenders and potential buyers, They are often directly remunerated by the lender. The broker helps you find the best offer.

The Real Estate Agent : provides intermediation between the seller and the buyer.
He has a duty of providing good advise and loyalty to the both parties and his activities are covered by his financial guarantee.