The Elephants qualified for the Cup of Nations decider after skipper Yaya Toure put them ahead courtesy of a 20th-minute belter only for Congo DR to draw level almost immediately from the penalty spot through Dieumerci Mbokani.
Gervinho restored the Ivorians' lead four minutes from half-time, and Wilfried Kanon wrapped up the victory in the 68th minute.
"I did not like this game. We played too easy and did not respect an opponent who fought back to beat Congo Brazzaville in the quarter-finals," said Renard. "We did not show enough determination - probably the small crowd did not give us the right atmosphere to do so.
The coach, who won the African title with Zambia in 2012, singled out Yaya Toure for special praise. "Yaya may not be at his high level with Ivory Coast, but he sacrificed a lot for this team. He has worked very hard for this team," he said.
The Frenchman also praised Congo DR coach Florent Ibenge, saying he has proven his worth after guiding V Club to the 2014 CAF Champions League final and taking his country to the Cup of Nations semi-finals.
"What is most important is competence, not the colour of your skin," he said, praising the only African coach to reach the knockout stage of this tournament.
Ibenge said: "Renard took me by surprise with his game plan. He was very intelligent by changing his game, defending and also playing fast counterattacks."