Richard Duhautois Conservatoire des arts et métiers (CNAM)-Lirsa and CEET   29 promenade Michel Simon Noisy-le-grand, 93160 France   richard.duhautois@lecnam.net             JEL Areas: J6 : Mobility, Unemployment, and Vacancies: General J3 : Wages, Compensation, and Labor Costs: General