AGRICULTURE - COMMON ORGANIZATION OF THE MARKET - IMPORT AND EXPORT LICENCES - SYSTEM OF SECURITIES - OBLIGATION TO IMPORT OR EXPORT - FULFILMENT - FURNISHING OF PROOF - PERIOD - FAILURE TO OBSERVE PERIOD - PENALTY - LOSS OF WHOLE OF SECURITY - PRINCIPLE OF PROPORTIONALITY - INFRINGEMENT - ARTICLE 3 OF COMMISSION REGULATION NO 499/76 - INVALID