OL will top Group I regardless of their result against Hapoel Kiryat Shmona, having already picked up 13 points to lead by five, while Hapoel will finish bottom unless they win and Athletic Bilbao lose to Sparta Prague.
With Lisandro Lopez, Jimmy Briand, Yoann Gourcuff and Dejan Lovren all missing out due to injuries, Garde will take the opportunity to assess several fringe players and youngsters in his side's 200th game in continental competition.
Garde said at a pre-match press conference screened on the club's website: "Everything is decided in terms of the standings.
"The importance of the game for me is to get a marker on some young players and others who have not played much in recent times.
"It is a great opportunity without much pressure. They are desperate to seize their opportunity."
Goalkeeper Anthony Lopes is set to play only his second match for the club, and his first at the Stade Gerland, having previously featured in the Coupe de la Ligue defeat at Nice.
He said: "To play in a European match at 22 is a dream.
"Since I was young I have watched the old players and to play in that stadium tomorrow, I will realise a dream and I am very happy."
Striker Bafetimbi Gomis sees a bright future for the club, and said: "It was important to get back to basics, to the academy, and it is good to throw the youngsters into the big pool when things are going well.
"The future of OL is the academy. The young players are happy, they can see what has happened in the last few months and the success of players like (Alexandre) Lacazette, (Maxime) Gonalons is also an example."
One player Gomis has particularly high hopes for is 18-year-old striker Yassine Benzia, who scored his first senior goal against Sparta Prague earlier in the European campaign.
"He works hard," he said. "He has made mistakes, apologised, grown.
"Young players are impatient to play, and that is a good thing."
Hapoel will hope to avenge their dramatic defeat on matchday two, when they drew level from 3-1 down only for Gueida Fofana to head a late Lyon winner.