As a citizen from a member of the European Union, there are no particular problems to work in France.
The French title for physiotherapist is kinésithérapeute. To work as a kinésithérapeute in France, you need an official diploma. If you are from another country, you need to check whether the diploma obtained is recognized as equivalent in France.
This document http://www.ordremk.fr/wp-content/uploads/2011/07/Guide_CNOMK.pdf seems to mention that the Hungarian three-year diploma is considered equivalent to the French one:
La validation des diplômes délivrés par les 4 universités hongroises
correspondent bien au diplôme français. Ces facultés de médecine sont
situées à Budapest, Szeged, Pécs, Debrecen.
I would consider soliciting the French embassy in Hungary to check the diploma equivalence.
Notice that the candidate must also be able to speak/write French sufficiently to deal with customers and administration.