In a statement, the two family-owned companies said the move would "optimise" operations amid fears of a downturn in the global shipping industry due to global economic weakness.
The statement said the partnership would affect the companies' Asia-Northern Europe, Asia-Southern Africa and South American routes.
"The agreement offers us new opportunities to optimise the use of our respective fleets, improve our transit times and increase our performance," MSC Vice President Diego Aponte said in the statement.
"We have decided to step up our partnerships, which reflect a commitment to long-term cooperation and will enable us to offer customers improved solutions and services," CMA CGM Group CEO Rodolphe Saade said.
The two groups will nonetheless remain commercial competitors and the partnership will not involve an exchange of capital.
Sources connected with the deal told AFP it would take effect in two weeks.
CMA CGM has suffered from debt problems and in September ratings agency Standard and Poor's revised its outlook on the shipping giant to negative, warning that it was at risk of breaching conditions on its debt.