Translate the following English sentence to French:
"Finally, and this is certainly the most serious issue, what cooperation policy do Member States intend to implement as of now in order to fight not only against the fly-by-night street trader, but more especially against organised crime, which nowadays apparently is becoming the real beneficiary of this expanding sector of activity?"
Enfin, et c' est certainement là le plus grave, quelle politique de coopération les États membres comptent-ils engager dès maintenant pour lutter non seulement contre le vendeur à la sauvette, mais surtout contre le crime organisé qui semble devenir aujourd' hui le véritable bénéficiaire de ces activités croissantes ?