While the catacombs were not officially created by the king, they were built during a time of significant urbanization in Paris. The city's cemeteries were overflowing, and the practice of transferring bones from overcrowded graveyards to the abandoned underground quarries started in 1786 under Louis XVI's rule.
Therefore, although Louis XVI was not directly involved in the construction of the catacombs, his reign saw the beginning of the practice that led to the formation of this famous underground ossuary.