Faithfull, 66, spent the last four weeks in the hospital, but is now home in Paris, recovering from her injury, the BBC said Thursday.
Exactly how she was hurt has not yet been disclosed.
"I broke my back in July and hoped and prayed I would be better enough to be able to do the performance on Aug. 17, although it's not very long, but my recovery was going well. Alas. I have never been to the Lebanon though I know it through books. It looks like one of the most beautiful places in the world," Faithfull said in a letter to fans in Beirut, canceling Saturday's concert.