Translate the following English sentence to French:
"In addition, we need - and this is my first recommendation - a legislative act that includes those offences which are to the detriment of the Union' s financial interests, and in which main principles are firmly established."
À cette fin, nous avons besoin - première recommandation - d'un acte juridique qui ancre les délits portant atteinte aux intérêts financiers de l'Union et les principes directeurs.