Ferrari on Saturday morning removed its controversial high rear wing for the start of the final pre-qualifying practice session in Barcelona.
The FIA was overnight looking into the legality of the wing, whose technically 3cm higher-than-legal height exploited a loophole about slot-gap separators.
"It's a very clever interpretation of the rules and we've got to decide whether we think it's a good interpretation of the rules," said technical delegate Charlie Whiting on Friday.
Reports in Italy had suggested Ferrari was likely to get a one-race reprieve and would only have to remove the wing for Monaco and beyond.
In fact, Whiting told Ferrari to remove it immediately.
"(The cars) are fitted with a standard rear wing after the team was told that the solution tested yesterday could be declared illegal," confirmed the Maranello based team.