This fortress, shut in on all sides by hills, was entirely without bomb-proof protection; direct approach from the south was, on the other hand, rendered difficult by artificial inundations, and on the west and north by swamps. General von Kameke therefore decided to await the result of a heavy bombardment before resorting to a regular attack. Batteries were erected on both banks of the Moselle, and on the morning of the 22nd eighty-five guns opened fire. At first the fortress answered briskly. In the following night the infantry detailed to the task of throwing up the first parallel, advanced to within 600 paces of the west front, but, in consequence of pouring rain and the condition of the ground the work made but small progress. However, on the 24th at mid-day the commandant proposed negotiations for the surrender of the place. The garrison, 4000 strong, with the exception of the National Guard belonging to the place, became prisoners and were sent to Germany; and 199 guns, besides a considerable amount of supplies, arms and ammunition, fell into the hands of the conqueror.

The 14th Division was now required to lay siege to the northern frontier fortresses, which would occupy it for some time. The 13th Division, by orders from the supreme Head-quarter, was assigned to the operations in southern France.