Article 40 of the Cherpion Law of July 28, 2011 (L. n°2011-893, JO 29 juill.) amended Articles L. 8241-1 and L. 8241-2 of le Code du Travail. It did not mention - let alone restrict - remote/home working for interns. Instead, it:
introduces measures that strengthen the legal framework regulating internships. The new law states that internships:
cannot consist of tasks that could be undertaken by a worker in a permanent position within the organisation;
must be established through a tripartite contract signed by the employer, the intern and their educational establishment;
must offer training to individuals and be integrated into the intern’s degree or other training. Source
The only reference to the intern's (i.e. employee's) place of work can be found in 8241-2, which states:
The non-profit labor loan between companies requires:
An amendment to the employment contract, signed by the employee, specifying the work entrusted to the user company, the hours and the place of performance of the work, as well as the specific characteristics of the workstation.
Note that these two provisions in le Code were further amended in 2015 and 2017 respectively to the versions currently in force with no change to the quoted requirement.
Also, I'm not familiar with the current COVID-19 restrictions in France but I find it odd that remote working is not being considered. See the Université de Paris FAQs for an example of where it is being implemented:
Internships outside of Université de Paris can take place or continue on face-to-face basis, however, only when working remotely is not possible or relevant.