If you hold a passport from a non-European country, you may need a visa to gain entry to France. The French Government has a wizard that helps you to see if you need a visa: Do you need a visa ? | France-Visas.gouv.fr
Before making a request for a visa and a 'Convention d'Accueil' (Hosting agreement for a foreign researcher), the principal investigator of the experiment should complete the A-form with the names of the users coming to the ESRF. It is critical at this point that each user makes sure his/her safety training is up to date.
Once your A-form is completed, you can contact the CRG office at the ESRF (copying in Laurence Bouchenoire) to request your 'Convention d'Accueil'. The CRG office will use part of the information contained in the the A-form in addition to those detailed in the link below: