Reuters has an article in English:
Air France asks passengers for refuel cash at Damascus stop
As
irishguy28 says, it seems airlines may not have procedures in place to pay for fuel in some locations where they do not normally land - especially if relations between the two countries involved are strained. (The article indicates that the captain normally carries a credit card for such emergencies - but in this case, the credit card was not accepted).
There was a similar incident in 2005 (
American jet makes emergency landing), when a NWA DC-10 made an emergency landing in THR due to a (false) fire warning - and then struggled to find a way to pay for the fuel they needed (although I don't think they asked the passengers to contribute, on that occasion).
In the NW case, I'm surprised they couldn't have just asked KL (who had regular operations in THR) - but for the current AF case, I'm not sure any SkyTeam partners still serve DAM...