The French company is offering English-language programs at various levels for its employees and says (this is the entire paragraph):
Les niveaux de compétences préconisés varient suivant la Workforce, et le grade du collaborateur. Chaque niveau est détaillé dans la grille du prestataire retenu par la société . Chaque niveau dispose d’une équivalence dans l’échelle des compétences européenne - Common European Framework (cf. attachements)
So ªcontractorª would not seem to fit. Seems to be more of some kind of framework or schedule, but what?
The "prestataire" is a contractor. The grille du prestataire - if we are talking about delivering a training course based on job grades and competencies - would be something like "the consultant's/trainer's (classification) table. My understanding is that the consultant has a matrix table with job grades and competencies on the one side and the level of English needed on the other based on the fact that the higher the trainee is within the chain of command, the higher level of English he is to be taught. Hope this will help.