Cost of living in Rennes (France) is 71% 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 592 prices entered by 39 different people.
For example, you would need at least Mex$ 82,124 (€3,645) in Rennes to maintain the same standard of living that you can have with Mex$ 48,000 in Zapopan.