Giustini has been with White & Case since he qualified in New York in 1986 and moved to Paris in 1987. He will join Clifford Chance's Paris office at the end of May.
He is currently co-head of projects for Europe, the Middle East and Africa, and his clients include BNP Paribas, Société Générale, Dexia, International Finance Corporation and US Eximbank.
Giustini says he is moving to Clifford Chance because he is impressed with its merger with Rogers & Wells.
"It is the first firm to have [full-service] offices on both sides of the Atlantic. At Clifford Chance I'll be in a UK law firm, but I'll also have US capability," he says.
At Clifford Chance he will work closely with Michael Elland-Goldsmith, who heads the five-partner Paris practice.
Elland-Goldsmith's te-am is currently advising the French government on the FF2.5bn (£235.8m) construction of the Millau Viaduct in the South of France.
It also advised opposite White & Case on the financing of the Chad-Cameroon pipeline project.
Giustini says that whereas Clifford Chance's Paris team has tended to focus on domestic projects, his practice is far more international. "It will be an interesting challenge to put these two elements together," he says.
Clifford Chance managing partner in Paris Yves Wehrli says that Giustini will complement the existing practice.
"He's working for some of the same clients as us, but not to the same intensity. He also has a strong reputation in Africa where we're not particularly active. His international experience in oil and gas fits well with the largely domestic focus of our group as well as the firm's strengths in infrastructure, rail and road."
Wehrli says that the office will continue to grow its projects and finance practice.
"We'll expand through a mixture of organic growth and lateral hires," he says. "Our plan is to double the size of our finance practice in the next five years."