| Mr. | Anderson | Jess's fostered father. |
| Benjamin | Daniels | Jess's half-brother. Missing. Aka: Ben. |
| Monsieur | Gus | Mimi's old stuffed toy. |
| Jess | Hadley | Ben's half-sister. |
| David | Mallet | Sophie's hairdresser. |
| Theo | Mandelson | The Paris editor. |
| Sophie | Meunier | One of Ben's neighbors. Jacques's wife. |
| Paula | Rego | A visual artist. |
| Antoine | | Ben's neighbor over at the 1st floor. |
| Benoit | | Sophie's silver whippet. |
| Blanchot | | The police commissioner. |
| Camille | | Mimi's flat mate. |
| Concierge | | The gatekeeper of the building. |
| Dominique | | Antoine's wife. |
| Elira | | The concierge's daughter. |
| Guy | | One of Nick's friends. |
| Harry | | One of Nick's friends. |
| Henri | | Mimi's art teacher. |
| Irina | | The mystery girl. |
| Loulou | | Camille's friend. |
| Mimi | | The girl who lived on the 4th floor. Aka: Mervielle. |
| Nick | | Benjamin's friend and neighbor. Aka: Nicolas. |
| Suki | | The cat. |
| Victor | | The guy that Jess met at the party. |
