Police are appealing for information and witnesses after the fight broke out in the Oxford Street store.
Two men were taken to hospital with stab injuries after a fight in Selfridges afdelingswinkel.
The London Ambulance Service and the Met Police attended the scene.
Two men in their 20s were taken to hospital with stab injuries and later discharged.
Een of the injured men was arrested, as was a third man also in his 20s, the police said in a statement.
Both have since been bailed pending further inquiries.
Any witnesses and anyone with information is asked to call 101 ref CAD 5667/21jan. To remain anonymous, please contact Crimestoppers.