Translate the following English sentence to French:
"Therefore, once our legislation has been brought into line, we must follow this up immediately with appropriate law. We must also put in place systematic controls and finally apply the 'polluter pays' principle of responsibility which is, of course, supposed to be a deterrent."
Donc, il faut qu'il y ait un droit de suite, après la mise à niveau de notre législation, il faut aussi mettre en place des contrôles systématiques et enfin appliquer le principe de responsabilité pollueur/payeur, qui est naturellement un principe préventif.