"It was advised that my contract with the Sharks was not going to be registered until just before round 12 which placed the club in a difficult position regarding their financial position and if, or how, I may earn an income," Barba said.
His deal would place him as one of the best paid union players in the world behind All Blacks legend Dan Carter and Toulon teammates Matt Giteau and Leigh Halfpenny.
Barba has already been put on notice that off-field misdemeanours that blighted his brilliant league career won't be tolerated by the French club.
Toulon's rich owner Mourad Boudjellal told French newspaper L'Equipe that Barba's deal had strict behavioural clauses and he would be sacked following the first infraction.
"In regard to the incident at the back end of last year, I take full responsibility, I made a terrible mistake and I own it and will have to live with it."
Barba had hoped to move to France on a short-term deal while serving his 12-game NRL ban for a second positive illicit drugs test. However, Greenberg declared Barba's suspension would not start until any overseas playing commitments were completed, virtually ruling Barba out of a return to the NRL this year.
The rich list
World rugby's highest paid players (all in NZD)
• Dan Carter - $2.43 million per year (Racing 92, France)
• Ayumu Goromaru - $2.43 million (Toulon, France)
• Matt Giteau - $1.57 million
(Toulon, France)
• Kurtley Beale - $1.31 million
(Wasps, England)
• Ben Barba - $1 million
(Toulon, France)
• Ma'a Nonu - $1 million
(Toulon, France)
Source: news.com.au