According to the Commission interpretative communication and a consistent ECJ case-law in that matter, contracting authorities are bound to comply with the fundamental rules of the Treaty even when contracts are excluded from the scope of the Public Procurement Directives. These rules include the free movement of goods (Article 28 of the EC Treaty), the right of establishment (Article 43), the freedom to provide services (Article 49), non-discrimination and equal treatment, transparency, proportionality and mutual recognition. In practice, this can be best achieved through: non-discriminatory description of the subject-matter of the contract; equal access for economic operators from all Member States; mutual recognition of diplomas, certificates and other evidence of formal qualifications; appropriate time-limits; and a transparent and objective approach. The Commission strongly advices contracting authorities to comply with this set of basic standards in all cases. Moreover, it has to be pointed out that under ECJ case-law, EU nationals are under an explicit judicial protection against discrimination deriving from the Community legal order.