The couple, who have two kids, Lily-Rose, 13, and 10-year-old Jack, announced the end of their relationship this week and Paradis is set to walk away with the huge sum even though they have never married, reported Sun online.
Depp, 49, is expected to make the huge one-off payment to Paradis, 39, to keep their relationship amicable, rather than going through a messy court battle.
"If the couple had been married, Mr Depp's wife would have been able to simply claim 50 per cent, child support payments and alimony. However, because they are not married this does not apply. The partner would have to file a civil suit and go to court," Hollywood lawyer Robert Naschin said.
"Litigation is expensive and could run into extremely high figures. This won't be a monthly payment plan - he will make a lump sum payment as a settlement," Naschin added.
The "Pirates of the Caribbean" actor earned a reported 50 million pounds last year alone and has an extensive property portfolio which includes homes in Paris, Venice, the Hollywood Hills, Los Angeles and Norfolk along with a private island in the Bahamas.
According to friends, the pair tried for months to save the relationship but have known for weeks that it couldn't be saved.