"In France, a retired person can work to earn extra money, equivalent to a maximum of one third the value of their pension."
It is a little complex and ambiguous, because it could be read that the money they earn is part of the pension (e.g. work = 1/3 + penion 2/3 = 100% of income). I am assuming you mean that they can earn money equivalent to 1/3 of their pension income? It would be eas