In his youth, Philip Constantin was a cataphile, the term given to those obsessed with the Paris Catacombs.  He extensively explored the network of catacombs under the city. He joined the police force fully intending to enlist for the cataflics, a division dedicated to patrolling the catacombs after it was deemed illegal to descend them in 1955. However, they weren't hiring at the time.  The National Police Force was made aware of the Ghostbusters' brief stay in Paris on Erland Vinter's behalf and were permitted to operate in pre-approved areas only. Lieutenant Constantin was not amused to learn they were battling two Unknown Soldier Ghosts at the Arc de Triomphe, a national landmark, amid tourists and civilians. Once the ghosts were trapped, Constantin started questioning their judgment in engaging them. Peter Venkman explained they were chasing Class 4 ghosts in New York City, got turned around on the way back to hotel, and they had to suddenly deal with angry ghosts from a hundred years ago in Paris. Constantin reminded them of the restrictions of their operating in the city and announced their equipment would be confiscated and they would be taken into their custody until everything was sorted out. Peter demanded a phone call and a baguette.
Two hours later, Kaia May mistakenly released the two ghosts while searching for the Poveglian Artifact. Amid the chaos that ensued, Constantin received a call from the President of France. He asked for one of the Ghostbusters. Constatin found them in the room where the equipment was being kept and asked them to come quickly to his desk. Peter took the call. Afterward, Constantin apologized to the President and assured him Peter was not being disrespectful, just being a typical American like in the movies. The President ordered Constantin to escort the Ghostbusters through the Louvre and authorized him to shoot them if any art was irreparably damaged.  Constantin led the Ghostbusters underground through the Paris Catacombs to seek an alternative way of entering the Louvre so the ghosts wouldn't be immediately alerted to their presence. Ray Stantz lent him the Ghost Taser so he could at least protect himself. After they met the ghost of Jean l'Ecorcheur, Constantin tasered him. Jean retaliated by animating the David, Venus de Milo, Code of Hammurabi, and Mona Lisa. Constantin watched in horror as the Ghostbusters disintegrated the works of art with Slime Spritzers. He predicted his career was over. Eventually, he caught up to the Ghostbusters in the Tuileries Garden. He noticed Jean had to act in order to defend the Poveglian Artifact, implying it was vulnerable. He proposed they distract Jean with a frontal assault while he went around and took a shot at the artifact. The plan worked. The artifact was fried and Jean was trapped. Constantin reminded the Ghostbusters they still needed to make sure the Unknown Soldier Ghosts weren't still in the Louvre.
- Philip appears to be visually based on actor Jean Reno
- In "French Kiss," Reno portrayed Inspector Jean-Paul Cardon.
- Philip's cap indicates he is a Lieutenant in the National Police Command and Management Corps.
- On page 12 of Ghostbusters International #5, Peter refers to Constantin as "Clouseau," a nod to Inspector Clouseau from the "Pink Panther" franchise.
- Ongoing Series
- What Came Before! Page (2016). IDW Comics- "Ghostbusters International #6" (2016) (Comic What Came Before! page). Narrator says: "After managing the situation at the museum and trailing the assassin's specter to the nearby Tuileries Garden, the boys in gray managed to trap the entity -- with the help of Philip Constantin, of the National Police Force."
- Lieutenant Philip Constantin (2016). IDW Comics- "Ghostbusters International #5" (2016) (Comic p.2). Lieutenant Constantin says: "When I was younger, I was very much the cataphile."
- Lieutenant Philip Constantin (2016). IDW Comics- "Ghostbusters International #5" (2016) (Comic p.2). Lieutenant Constantin says: "In fact, I joined the police force with the full intention of enlisting in the division that patrols down here. They weren't hiring."
- Lieutenant Philip Constantin (2016). IDW Comics- "Ghostbusters International #5" (2016) (Comic p.3). Lieutenant Constantin says: "I have full authority to shoot you if anything is irreparably damaged."