While Koscielny is wary of the threat Brighton pose, he is confident Arsenal will secure their place in the fifth round of the FA Cup.
"Whether it is the FA Cup or the French Cup, it's all the same: the smaller teams always want to win against the big teams," he told arsenal.com.
"They would like to beat Arsenal, so it will be hard and we will have to fight. We must play our football to win this game.
"We are favourites, so there is a little more pressure when you play. It will be difficult but if we keep our quality and play our football, we can win."