Lukaku was shown a straight red card in the 87th minute of Sunday's 1-1 draw in Rome after clattering into Kouame, leaving Roma with nine men after Nicola Zalewski was sent off midway through the second half.
Ivory Coast forward Kouame was not seriously injured by the tackle and Lukaku was spared a potential three-match ban for violent conduct.
That means that Lukaku will only miss Sunday's trip to high-flying Bologna, who are level on 25 points with fourth-placed Roma and have won their last four home matches.
The Belgium striker's absence leaves Roma short-handed in attack as Paulo Dybala picked up the latest in a string of muscular injuries shortly after setting up Lukaku's fifth-minute opener.
Dybala's replacement Sardar Azmoun also suffered a thigh injury and will miss the weekend's match and his team's final Europa League group match against Sheriff on Thursday.
Escaping sanction completely was Ibrahim Sulemana, who has not been punished by the authorities despite knocking out Kristian Thorstvedt's teeth in Monday's last gasp 2-1 win over Sassuolo.
Cagliari moved out of the relegation zone after two stoppage-time goals turned the match around, but Sulemana wasn't even booked after elbowing Thorstvedt in the mouth and leaving the Norway midfielder bleeding from the mouth.
Italian media report that Thorstvedt, who finished the match, picked up two teeth from the field and showed them to Sassuolo coach Alessio Dionisi.
Maurizio Mariani judged the incident to be an accident and VAR officials did not get involved to sanction Sulemana.
