The 38-year-old was in the stands to watch Toulon beat Brive 18-3 in the Top 14 on Saturday, with his presence seeming to support rumours that he is ready to head overseas.
Toulon have lost new signing Bakkies Botha to an Achilles tendon injury and Shaw is being seen as the perfect short-term replacement.
The former Bristol lock has not been offered a new deal with London Wasps, meaning he is currently without a club.
A Lion in 1997, 2005 and 2009, Shaw was a member of England's recent World Cup squad where he featured in the games against Georgia, Romania and France.
He was tipped to rejoin forces with ex Lions and Wasps boss Sir Ian McGeechan at Bath but the south of France now seems like the most likely destination for the 71-times capped second row.