So to clarify it's a French bayonet that was made in Germany?
Yes. The blade was made by a commercial German company under contract with the French. Once the order was filled, it was sent to the French government who finished assembling the bayonet at their facility in Tulle.
International trade like this was fairly common in Europe and Asia throughout the ages. For example, an English sword could have it's blade forged in Germany with the iron/steel sourced from Syria. Fittings and finishing materials could be imported from Spain and Italy.
Another example is a long forgotten Persian glassware that was gifted to the Emperor of Japan from the Persian ruler in the 6th century. When the Emperor passed away, his widow ordered everything that reminded her of her late husband to be stored away. It wasn't until 1980s that the Imperial Household Agency allowed the warehouse to be opened and contents examined. Only 6 items are allowed to be examined every year.
One of the first items uncovered was that Persian glassware that literally rewrote history. Before it was rediscovered, it was believed that glass was introduced to Japan by the Portuguese in the 15th century.