At export to the EU or a CEFTA country, is it allowed in the proof of origin to mention a country of origin different from Moldova? For example, if goods imported in Moldova with a proof of origin and after some time, without being used, are to be sent wholly or partially, to the country from which they have arrived or to another one?

Yes, the PEM rules of origin provide for such an option based on the provisions for diagonal cumulation (cases of retaining the origin). The proof of origin to be issued in Moldova should be based on the proof of origin for the goods in question issued in the partner country from where the goods have been previously imported in Moldova. It should be noted that in case a EUR.1 is issued at export from Moldova, it would be according to the normal procedure, not as a replacement certificate (intended for use in the importing country).