All internships need a signed agreement.
In the agreement, the term “Etablissement d’accueil” refers not to the laboratory but to one of the structures that hosts the laboratory: it can be the University to which it is attached, the CNRS, etc. The host laboratory will tell you. The agreement (3 copies in general, 6 for Paris-Sud/Paris-Saclay) must be signed by the Head of this structure, by the internship mentor, by the student, by the “enseignant référent” (i.e., your principal professor in France), and by the Head of the University in which you are enrolled in France.
Depending on your University of enrollment, download the relevant files below to start the round of signatures:
SORBONNE UNIVERSITE :
Université Paris-Diderot :
If your internship is abroad, you also need an internship agreement.