The Premier League outfit were drawn in Group F along with last season's runners-up Borussia Dortmund, Ligue 1 outfit Marseille and Rafael Benitez's Serie A table-toppers Napoli.
And the Frenchman feels that the difficulty of the group means that 10 points should be enough for his side to secure a place in the round of 16.
"If you look at the group, I would say yes it is the hardest group because all the four teams have a chance to qualify," he said.
"That means that every game is basically a very important one. On average you need 10 points to qualify so that gives you the task. Ten points in a group as difficult as that could be a reasonable number to get through."
Arsenal begin their campaign with a visit to the Stade Velodrome to face Marseille on Wednesday, and the 63-year-old emphasised that performances away from home will be particularly important to secure qualification.
"It will play a big part because it is difficult to predict that you will absolutely win your three home games," he continued.
"You need points away from home and, like in every competition, the start is very important for the confidence of the team and to put you in a good position.
"Whether it is home or away, it is the same basically, we come here and we will try to win the game."
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