Résumé : This paper argues that the TTIP negotiators may be underestimating some of the risks associated with the treatment of public services. De facto opening the door to supranational regulation of key public services may be well intended to protect investors. But when the bargaining power of these investors operating in non-competitive markets (which is the case for most public services) becomes excessive as a result, the experience of developing countries in interactions with many of the same large players points to risks. It is likely that outcomes in terms of the usual policy criteria (efficiency, equity and fiscal viability) will not be as positive as promised in an environment in which regulation ends up weaker (because it is captured or less specialized). Ignoring these lessons and failing to internalize them in the design of negotiation is likely to cost Europe.