If finalized the takeover will create Europe's largest automobile manufacturer after Volkswagen.
The supervisory board of French carmaker PSA has approved the takeover of General Motors' European subsidiary, which includes the Opel and Vauxhall brands, and a formal announcement is expected on Monday, an informed source said on March 3.
The move will create Europe's largest automobile manufacturer after Volkswagen, the source said, speaking on condition of anonymity.
The negotiations, revealed last month, were "swiftly concluded," the source added.
The deal "will be sealed on Monday morning in France and in Germany," the source said, adding that both sides "were very enthusiastic and satisfied."
The planned takeover of the Opel division by PSA, which owns the Peugeot and Citroen brands, was unveiled in the middle of February.
It sparked fears in Germany and Britain that the prospective new owner could cut non-French jobs.
PSA boss Carlos Tavares had said earlier he wanted to develop the "iconic" Vauxhall brand as "part of Britain's automobile sector heritage".
Vauxhall employs around 5,000 people in Britain. Opel operates some 10 factories in Europe spread across six countries, and had 35,600 employees at the end of 2015, 18,250 of them in Germany.
Founded in 1862, Opel, with its lightning-bolt emblem, is a familiar sight on German and European roads.
But in recent years the firm has booked repeated losses, GM around $15 billion since 2000.
Copyright Agence France-Presse, 2017