French term (edited): entreprise de gros �uvre

There may be no need to be any more specific (though this is really quite specific in itself), depending on the content of your document. Whilst other (sub)contractors working on the job may also be (kinds of) building contractors, they will most likely go under some other name, e.g. plasterwork contractor, partitions contractor, flooring contractor, etc.

building contractor - see builder

builder - (2) A building company, usually a main contractor for large building projects and associated external works. The biggest builders employ hundreds of professional staff and site personnel to do each specialist job? ...

[Scott, Penguin Dict of Building]