Nicolas Sarkosy (left) said Brazil was important for world stability
Brazil has signed an 8.6bn euro ($12bn; £8.2bn) defence deal with France to buy 50 helicopters and five submarines.
The deal includes transfers of technology intended to help Brazil develop its own arms industry.
It was signed at the end of a two-day visit to Brazil by French President Nicolas Sarkozy.
France will provide technology for the submarines, of which four will be conventional and the fifth will be nuclear-powered.
They will be partly built and assembled in Brazil.
The 50 EC725 helicopters will be built locally by Helibras, a subsidiary of Eurocopter, which is part of the European aerospace company EADS.
The aircraft are expected to be delivered in 2010.
A French official was cited as saying that 6bn euros would go to French companies and 2.6bn euros to Brazilian ones.
Brazilian President Luiz Inacio Lula da Silva said the deal reflected Brazil's status as an emerging power.
"France is willing to... build an alliance in Brazil, to transfer technology so Brazil can have a defence industry that corresponds to its importance in the hemisphere, in the world," he said.
Mr Sarkozy said: "It is an historic decision because France believes that a powerful Brazil is an important element for the stability of the world."
Earlier in the visit he had argued that Brazil should have a greater role in international affairs and a permanent seat on the UN Security Council.