The striker has signed permanently from Leicester City through to 2022.
Slimani said, “I'm very happy, I really wanted to come, from the start of the season. Thank you for giving me this opportunity. When I was little, I often came to Givors, I always had that in mind.
"Lyon is among the best clubs in Europe. It's true that I haven't played a lot (in recent months) but I've worked a lot, with a lot of sacrifices. I can be ready in a week or two. I am combative, I give my all.
"I came to Givors when I was little, I came with my club to do tournaments! My job? I showed that I could play on one side or in the middle. There will be no problem. I can bring experience, fighting spirit. Everyone knows my qualities. My year in Monaco? I hope to do better, I want to help."
OL president Jean-Michel Aulas also said at Slimani's presentation: "We are very happy to welcome Islam. The opportunity presented itself, I thank Juni who took matters in hand as usual to allow Moussa (Dembélé) to leave on loan and welcome Islam. If things go well, why not go beyond (2022),?"