The discrimination by the prices indicates the modulation by Agent Prix of sound Offre according to the known or supposed characteristics request.

Classically, one distinguishes three types of discriminations by the prices according to the Information available to the discriminating agent:

1. Discrimination of first type, or perfect discrimination : the agent knows propensity to pay each agent, and proposes to him exactly the maximum price that it is ready to pay.
2. Discrimination of second type: the agent knows a characteristic of the potential customers imperfectly related to their propensity to pay. He then proposes a menu of price according to the methods of this characteristic.
3. Discrimination of third type: the agent knows or can inférer the Distribution in the population of a characteristic related to propensity to pay. He proposes then a menu of couples (quality, prices) so that the customer potentials Autosélection is nent.

Perfect discrimination

One speaks about perfect discrimination when the offerer can know exactly propensity to pay each consumer who presents himself and to propose to him a price equal to this propensity. It captures then the entirety of the Surplus resulting from the transaction. Perfect discrimination can also rest on the knowledge of any characteristic perfectly correlated with propensity to pay.

In practice, perfect discrimination is impossible. There exist however cases where certain agents are able to evaluate propensity to pay of their customer and to carry out a discrimination of this type. One can take for example the practices of certain craftsmen in residence (plumbers, glaziers, metal workers) whose prices vary according to the estimate that they make of the richness of the customer and the urgency of repair.

Although neutral in the field of the transaction, the transfer of surplus generated by perfect discrimination is done with the detriment of the Consommateur. This is why the Droit of consumption often prohibits discriminations of this type by forcing the posting of the prices so as to fix the offer before the transaction takes place (bars, restaurants, hairdressers…). As regards the Undertaken S, the Droit of competition promotes a certain transparency by posing the obligation for the supplier to communicate his scale of price and its general terms of sale to the retailer who makes the request of it. This obligation of communication posed in article 441-6 of the Commercial law is however not preceded by an obligation by establishment. The supplier can consequently draw up different documents for each company customer because the text of article 442-6 of the Commercial law sanctions discrimination only insofar as it " create an advantage or a disadvantage in the concurrence".