Agents in France charge anywhere between about 2.5% to 8% with 5 to 6’% being fairly normal. Unless stated, agents fees are paid by the buyer.
Indeed all fees are paid by the buyer with the exception of the diagnostics and '(unusually) any specific report or survey relating to the property as required by law. A building survey is not the norm but again those fees would be paid by the buyer.
As far as notaires fees are concerned these are strictly controlled on a sliding scale according to the value of the property.
It is to be noted that it is a fallacy that buying through a notaire means that you do not pay agency fees. They also effectively operate as estate agents in their own right and will charge their own fees as set by themselves. The legal fees will be on top.
Since last year all agents, including notaires, are obliged to state the price of the property itself with their fees being stated independently. They can no longer ‘lose’ or masssge their fees into the sale price.
The best advice is to establish at the outset what percentage fee rate the agent or notaire is charging
to sell the property on behalf of the vendor. After that speak to a notaire to find out what exactly the conveyancing fees will be. Any lower offer accepted should reduce both the agency fees (calculated as a percentage) and the legal fees (calculated on a sliding scale).
In summary all fees with the exception of diagnostics are paid by the buyer unless alternate agreements are negotiated but there is no obvious advantage buying through a notaire. In fact buying through an agent can be advantageous because then you have two parties working for you to earn their commissions.
Of course the upside is that when you sell the property you only pay for the diagnostics. Remember the old maxim that you make your profit when you buy rather than when you sell so shop wisely.