The 29-year-old broke the same leg in October and was ruled out for three months of the current campaign.
"It is a broken fibula, the same leg," Arsenal manager Arsene Wenger [ Images ] told Sky Sports. "He was kicked on it, it has not happened alone.
"The guy closed him down and walked on him. I don't know if it was deliberate or not."
Sagna, who was a possible inclusion in France's squad for the Euro finals in Ukraine and Poland, had not played with Les Bleus since a goalless draw in Romania in a Euro 2012 qualifier last September.
France coach Laurent Blanc, however, has plenty of alternatives.
Olympique Lyon's [ Images ] Anthony Reveillere can play either on the right or left flank and Lille's [ Images ] Mathieu Debuchy produced a sterling performance in a 2-1 victory against Germany [ Images ] in Bremen in February.
Blanc is due to name two preliminary squads before making his final choice.
The first squad, unveiled on Wednesday, will feature players based abroad while the May 15 squad will feature home-based players.
Blanc is already without left back Eric Abidal [ Images ] who has undergone a liver transplant, and is likely to have to make do without holding midfielder Abou Diaby [ Images ] because of a calf injury.
France are drawn in Group D with England [ Images ], Ukraine and Sweden.