@Baptiste_k97
Please follow below steps :
1. you need a scheduled recurring flow to run daily
2. Use Get Past time to get the time in the past by 7 days
3. Use the Get Files Action to get the files you want to delete from the folder
4. Expression on Filter Query Right hand side
formatDateTime(body('Get_past_time'),'yyy-MM-dd')
Note: Do not forget single quotes between the format expression

5. Apply to Each and Delete files
