The Arsenal defender says it was difficult for les Bleus to lose their "best player" but insists they will recover and aim to win the trophy in honour of the injured Bayern star
The Bayern Munich striker was included in Didier Deschamps' final 23-man squad for the tournament in Brazil but a recurring back injury saw him ruled out shortly before the competition.
And Koscielny says that it was extremely difficult for the team to see their key player miss the tournament.
"It’s always difficult to lose team-mates to injury," he told Fifa's official website. "But given that Franck was our best player, it was even tougher this time.
"He’s very important in the dressing room; he communicates well with everyone. His passion is crucial. But other players have come in and the atmosphere has remained very good, even though we still have to deal with those absences."
Despite missing the 2013 Ballon d'Or nominee, Koscielny insists his side can fight for glory in Brazil, beginning with Honduras in their opening encounter.
"We now want to go as far as we can in their honour," he said.
"We know it’ll be tricky, because they [Honduras] are tough and tackle hard. But we’ve got a lot of different qualities. While we’re probably a more skilful team, we’re also capable of matching up with our opponents physically."