Nigel Willamson did a piece about YouTube as a source of archival footage for world music in the January/February 2009 issue of Songlines. He mentions Robert’s appearance with Tinariwen in Paris, 2007:

Tinariwen with Robert Plant
The clip of Tinariwen and Carlos Santana on stage playing ‘Amassakoul’ at the Montreux Jazz Festival is ten minutes long and beautifully shot. But although Santana seems genuinely thrilled to be playing with them, his sound is far too clean and at odds with the band’s earthiness. You’ll find far more excitement in the clip of Robert Plant and Justin Adams jamming tumultuously with the band on ‘Whole Lotta Love’ at a show in Paris in 2007. Even though there’s less than two minutes of it and the sound and pictures quality are dreadful, it beats that Led Zeppelin reunion by a Touareg mile.