Plot hole: When Ethan and Walker are waiting for Lane to drive by and knock him into the Seine, Walker realizes that Ethan was the agent who caught Lane. He says, "How long do you think he'll keep that to himself?" He says it as if Lane is going to see the White Widow or her brother, but since he hasn't left Ethan's side the entire time since the plane, wouldn't he know of Ethan's plan to take Lane before the brother could kill him?
Other mistake: When Solomon Lane is being extracted out of the sunken truck there are two divers breaking in. However just a moment later only Benji surfaces with the prisoner while Luther is on the lookout on the rib. (00:55:11 - 00:55:36)
Plot hole: Ilsa had no idea where the BMW was going - she was already on the bridge and in position when we see it turn left into the street, it could've easily have gone straight on.