PARIS, Feb 2 - The French official budget forecast of 1.7 percent economic growth this year is the "bottom level" of what is possible, government spokesman Jean-Francois Cope said in a radio interview on Monday. "We're very optimistic," Cope added in an interview on BFM radio. Various ministers have said in recent weeks they believe the pace of expansion measured in terms of gross domestic product is already at a level of around two percent or will hit it soon. Growth for last year is expected to have been marginal.//