Cost of living in Rennes (France) is 70% 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 509 prices entered by 38 different people.
For example, you would need at least Mex$ 83,142 (€3,650) in Rennes to maintain the same standard of living that you can have with Mex$ 49,000 in Zapopan.