Feyenoord fans threw a large inflatable banana in the direction of AS Roma's Ivorian striker Gervinho during Thursday's Europa League match.
Fan behavior was reportedly an issue throughout the first half of the match and eventually prompted a brief suspension of play.
Adem Ljajic scored in the first minute of first-half stoppage time to give Roma a 1-0 lead and was subjected to abuse from the Dutch fans.
The referee warned Feyenoord that the game would be called off if there was another racist incident, according to Italian reporter Tancredi Palmeri.
Feyenoord was sanctioned by EUFA in August for racist fan behavior in a match against Besiktas in July, when Feyenoord supporters chanted a racist insult at the visiting Turkish club.
- Dan Gartland