What are those black guys in paris doing with string on the street? Is it a con?

Question

In Paris on the streets near the tourist sites there are black guys with purple and pink coloured string who say stuff like "look here my friend, I want to show you something"

What are they doing? Is it a prank to scam you out of money or what?

Answer 1

And they often are illegal workers trying to gain few bucks out of tourists.

Answer 2

This from a post on Rick Steve's travel site:

They say they want to give you a gift and try to tie red string bracelets around your wrist. Then they harass you for money after giving this "gift".

Answer 3

yeah, they tell you they'll do a demonstration and ask you to tie the string around your finger while they braid it. then they want you to pay for it.... they're nice guys, don't let them touch you.

same with the gypsies when they ask you if you speak english.