The traditional agent’s commission: By law, offered prices must include the selling agent’s fee: the offered price should be followed by the letters FAI (« frais d’agence inclus »), and the ad should mention the full monetary cost of the commission. For example, an offered price of “590,000€ including a commission of 33,000€ TTC (inclusive of VAT)” means that, should 590,000€ be the price paid at the notaire, the seller will get 557,000€, the agent will get 27,500€ (5%) and the French Treasury will get 5,500€.
Agents’ fees (“commissions d’agence”) are not dictated by law. Those fees are freely negotiated between the estate agent and the seller, and may go as high as 7% (subject to VAT) of the “prix net vendeur” (net price to the vendor). They are usually between 3% (online agents and mandataires) to 6% (full service, luxury agents). As a buyer, you need to remember that you should incorporate the agent’s fee in the negotiation process, and that agents are often ready to reduce their fee in order to facilitate a sale.
As any for all agents' fees, the fee of a property finder is freely negotiated with the buyer — usually up to 3.5% (ex VAT) of the price of the property sought. As a buyer you should ensure that your property finder will help achieve a cost reduction higher than the fee he charges.
The buyer's agent fee comes on top on the listing agent fee - if a listing agent is involved in the transaction. But a good buyer's agent will justify his involvement by (at the very least) negotiating the overall price down by at least the amount of his fee.