Cost of living in Rennes (France) is 60% more expensive than in Zapopan (Mexico)
This comparison is lacking data. It provides a decent comparison, but it is not yet reliable. It is based on 370 prices entered by 36 different people.
For example, you would need at least Mex$ 83,075 (€3,749) in Rennes to maintain the same standard of living that you can have with Mex$ 52,000 in Zapopan.