Translate the following English sentence to French:
"It offers the prospect of large profits, however, for the multinationals, who have been working behind the scenes for around fifteen years to achieve their ends, i.e. having the derogations granted, on the occasion of a number of countries' joining the Union, extended to become the general rule."
Mais de gros profits en perspective pour les multinationales, qui uvrent en coulisse depuis une quinzaine d' années pour aboutir à leurs fins, c' est-à-dire obtenir que les dérogations accordées au gré des adhésions successives à l' Union deviennent la règle générale.