chugger n. A professional fundraiser who approaches people on the street to ask for money on behalf of a charity. Composite word created from charity + mugger.
The earliest citation of this word (according to Word Spy), is:

Is it just me, or where I live, or are there far more people demanding our attention in the street these days? This week I needed to walk from Tottenham Court Road tube in London, along Oxford Street, then north up Regent Street to the BBC. On the way I counted all the people who accosted me. There was a busker in the tube, two beggars … and no fewer than three “chuggers” which, I gather, is the term for charity muggers, those people with clipboards who want you to sign a standing order for their good cause.
—Simon Hoggart, “How to spot a loser — look for the pine cones and rice salad,” The Guardian (London, England), June 29, 2002

Those of you interested in fishing will be more familiar with the use of chugger as a topwater lure.
I’ll be brave and attempt a French equivalent: Attaquêteurs (attaquant (attacker) + quêteurs (collector)). Any other ideas?