Xavier Jugele, 37, was shot dead on Thursday while on duty on the famous Champs Elysees avenue, three days before the first round of France's presidential election.
The IS group claimed the killing by 39-year-old Karim Cheurfi, who was shot dead by police in a gun battle. Two other officers were injured in the attack.
Addressing hundreds of mourners at a ceremony at Paris police headquarters, Jugele's partner Etienne Cardiles spoke of his "extreme pain" at the death of the officer, who had campaigned for gay rights within the police force.
"This pain makes me feel closer to your comrades who suffer in silence like you and me," he said in a trembling voice, describing Jugele as a cinema and theatre buff who lived "a life of joy and huge smiles".
Echoing the words of the husband of one of the victims of the November 2015 Paris attacks, Cardiles said the killer would "not have my hatred".
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"I have no hatred, Xavier, because it is not like you and does not fit with what made your heart beat nor what made you a guardian of the peace," he said.
Jugele was the fifth policeman slain by jihadists in attacks that have claimed more than 230 lives across France since January 2015. Hollande posthumously made him a knight of the Legion d'Honneur, one of France's highest honours.
Shortly after Jugele's death it emerged that he had been among the first responders at the Bataclan theatre in Paris on November 13, 2015, where IS gunmen massacred 90 concertgoers.
He returned to the venue a year later when it reopened for a concert by British star Sting, telling a BBC interviewer he wanted "to celebrate life and say 'no' to terrorism".
Appeal for dignity
Hollande, who leaves office next month, appealed to the country's next leader to show "constancy, perseverance and coherence in the fight (against extremists), rather than escalation and divisiveness."
Far-right presidential candidate Marine Le Pen and her pro-EU centrist rival Emmanuel Macron, whom Hollande has endorsed, both attended the ceremony for Jugele.
Le Pen last week seized on the Champs Elysees attack as a vindication of her hardline stance on security and Islamic fundamentalism.
"Let us remain dignified and defend the peace," Cardiles urged.
