In so far as they are covered by Annexes 1, 2, 4 and 5 and the General Notes to the European Union's Appendix I to the GPA and by the other international agreements by which the Union is bound, contracting authorities shall accord to the works, supplies, services and economic operators of the signatories to those agreements treatment no less favourable than the treatment accorded to the works, supplies, services and economic operators of the Union.