++++ 1 . OFFICIALS - PROMOTION AND NOTICE OF VACANCY - EXISTENCE OF A LEGAL CONNEXION ( STAFF REGULATIONS, ARTICLES 27 AND 28 ) 2 . OFFICIALS - RECRUITMENT - NATIONALITY AS A FACTOR IN SELECTION - PROHIBITION IN PRINCIPLE - ADMISSIBILITY IN CASES OF EQUIVALENT QUALIFICATIONS - CRITERION OF GEOGRAPHICAL BALANCE ( STAFF REGULATIONS, ARTICLES 7 AND 27 )