On this page of the Assassin's Creed Valhalla Siege of Paris guide, you will find a detailed walkthrough of the Victory main story quest.
Return to Toka in Melun
This mission will begin immediately after defeating/rescuing Charles the Fat. When you reach the destination, you will trigger a longer cut-scene - you will only have one dialogue option. However, this does not affect the subsequent events. You learn that Count Odo will now be in charge, and Toka takes over for Sigfred.
After this conversation, you will be free to return home or stay in France. You can perform additional activities and explore the map.