At Cacib, 1,750 jobs will be cut globally, including 550 in France, said FO's representative for the bank, Bernard Péchard.
The bank's consumer credit branch, CACF, will see 600 jobs cut, half in France and half in the rest of the world.
Bank management held meetings on Wednesday with union officials representing staff at Cacib and CACF.
Péchard said he expected more job cuts would be announced when similar meetings are held at other Crédit Agricole subsidiaries, including leasing arm Calef, which has 3,100 employees, and equity broker Chevreux, which has 800.
On Tuesday union sources had said they expected "several hundred" jobs to be cut at Crédit Agricole, which last month reported a 65 percent drop in net attributable quarterly profit.
Crédit Agricole, one of the biggest banks in Europe by capitalisation, employs 160,000 people around the world, a third of them outside of France, while Cacib employs about 15,000 people globally, including 4,600 in France.
Like other French banks, Crédit Agricole has been hit by its exposure to Greek sovereign debt amid the eurozone debt crisis and last month revealed a 60 percent write-down of its holdings of Greek bonds.
The Moody's agency earlier this month downgraded its credit rating on Credit Agricole's long-term debt by one notch to Aa3, as it also announced downgrades on two other leading French banks, BNP Paribas and Societe Generale.
BNP Paribas expects to cut 1,400 jobs globally, mainly in its corporate and investment bank CIB, unions said last month, while Société Générale has also warned unions of plans to cut several hundred jobs.