There are a number of fundamental principles for public procurement that have to be observed when carrying out all procurements in the EU.
This guarantees that the 'four freedoms' (the free movement of people, goods, services and capital) promote a common internal market.
The procuring unit or authority may not discriminate a supplier based on their nationality, irrespective of whether the supplier comes from a country inside or outside the EU, and the enquiry documentation may not contain any discriminatory requirements.
Equal treatment principle
Tenderers and tender applicants must be offered as similar conditions as possible to take part in the procurement. The information must be the same and be available to everyone at the same time.
The enquiry documentation must not contain requirements that are unnecessary for the procurement in question. The requirements made by the procuring unit or authority must be related to and be in reasonable proportion to what is being procured.
The procuring unit or the authority is obliged to submit information about procurements and what tenderers and tender applicants need to actually do in the procurement process.
The procurement process must be predictable and open. The enquiry documentation must be clear and unambiguous and contain all the requirements for what is being procured. Similarly, the buyer must not deviate from the requirements that have been set.
A procuring unit or authority that wants a tenderer to prove that they meet certain requirements must accept proof and certificates from competent authorities in other countries.