Reports in France suggest Toulon coach Diego Dominguez's job is under threat, and Lancaster, 46, is viewed as a potential successor.
He left his role with England after their exit from the 2015 World Cup.
Since his departure, Lancaster has been an adviser to the Football Association, the NFL and British Cycling.
He is interested in the Toulon job, but is understood to still be keen on a role in the southern hemisphere, with posts in Australia at the Queensland Reds and the Western Force both available.
Former England boss Stuart Lancaster is meeting Toulon president Mourad Boudjellal this week as he seeks a return to full-time coaching.