I have worked in an estate agency, before setting up my own consultancy, and know many people who have worked or are working currently within agencies, both as employees (increasingly rare) or more commonly as an 'agent commercial', including using the auto-entrepreneur statute as their means of paying their tax and social charges.
As you are aware, you are entirely dependent on (part of) the agency commission received on sale of a property by you and on properties you bring to the agency for sale. Your success will depend on your ability to bring in buyers - some independent 'agents commerciaux' advertise or offer themselves as property searchers. In my expereience, the level of potential buyer enquiries was linked to the amount of passing trade (agency sited in a good location) and the amount of advertising (in recent years being cut back). Both of these are generally beyond your control.
Against this, you carry all your own costs - car, insurance (must be 'professional use' if you are taking clients in your car), petrol, mobile phone, computer, tax and social security. Some agencies are even charging 'rent' to their agents for 'use of the office facilities'.
There is a wide difference between busy urban (especially Paris) based agencies, who may have a waiting list of clients looking for apartments, and quieter rural ones. Some may deal mainly with French buyers and sellers (difficult if you are not native French) while others rely on a decreasing share of the British, Irish and other foreign markets. The latter are more lively in, say, Paris and on the Cote d'Azur.
The industry not surprisingly suffers high staff turnover, and I have seen friends give up after three or six months. You need also to check your contract carefully, as some I have read include an exclusive clause - for example, not allowing you to work for a competitor within 15 kms radius for 3 years after leaving! Probably unenforceable but most peolpe do not want to take the risk. You should also check the arrangements for allocating commissions - is everything shared, say among all the staff? Or is it dog eat dog and highly competitive? If the latter, individual agents will concentrate on trying to sell properties they have brought in (higher commission) and may not even show a potential buyer a property brought in by another colleague. A major disservice to the client but one of the faults of the system.
Based on personal experiences, I hope this gives you a few pointers - P-D de R.