A significant number of PhD (funded or not) and internships are listed on doctoral schools web pages. See, e.g., https://www.edpif.org/fr/recrutement/prop.php
If a PhD is advertized, and appears as “not funded”, the meaning is that a fellowship can be obtained during the yearly competition that often takes place between May and July. Be aware that the corresponding applications often have to be submitted rather early (April or May).
An internship in France or abroad cannot start without a properly signed internship agreement (“convention de stage”). The documents to be filled are here. Start this paper work as early as possible.
Internships (€€€ = with funded PhD)
[catlist name="Phd" numberposts=100]
[catlist name="Fundedphd" numberposts=100]