Translate the following English sentence to French:
"It is not an acceptable procedure that measures to improve the environment, which are in keeping with the Commission' s guidelines, cannot be taken because these are considered to constitute prohibited aid to shipyards."
Il est inacceptable que l' on se voie refuser, sous le prétexte d'aide illicite, le droit de prendre des mesures environnementales conformes aux lignes directrices adoptées par la Commission.