Sagna collapsed in the first half of Arsenal's 3-3 English Premier League draw with Norwich shortly after Johnson trod on his leg, the same one he broke earlier in the season.
"I think he did it on purpose," the 29-year-old told sports daily L'Equipe. "He stepped on my leg. Play continues, I get back on my feet. And when I tried to control the ball, I felt a crack, just like the first time at Tottenham.
"He stepped right where the plate was. I think the plate pressured (the bone). It's a neat break, just above the plate."
Sagna was confident he would return from the injury.
"That's how it is. It's football. It has happened to others before me," he added. "I came back once, I will come back a second time. Even stronger."
France are drawn in Group D with England, Sweden and co-hosts Ukraine.