This is known as obligatory resources.
In practice, you should allow an average of 600 euros per month to live in Lyon (accommodation, transport, healthcare, food and so on), plus travel costs and initial purchases when you arrive.
We would advise you to draw up a budget for your predicted expenses so that you can live comfortably in France and study in the best conditions.
You may also be eligible for MIRA grants for the Rhône-Alpes region (for students, lecturers and doctorate students).
CROUS (the regional centre for school and university student services) posts student jobs on its web site.