As the title suggests. I am reading To the Last Man by Jeff Shaara, and on page 92, he says, "...One more [fighter kill] would total eight, the milestone that would qualify him [Richthofen] for the Order Pour le Mérite, Germany's highest award for it's fighting aces." It's seems odd to me that Germany, after the Franco Prussian War and certainly during WWI, would avoid using the language, culture, or customs from an enemy combatant, especially considering the measures other Allied nations went through to distance themselves from German-sounding words (St. Petersburg to Petrograd, for example).
If you are not aware, as it may have not been included in a book on the Aces of World War I, the "Pour le Mérite" was established in 18th century Prussia, during a time when French culture was revered throughout all of Europe, including at the court of Frederick the Great. This is why it was in French in the first place despite coming from a non-French-speaking area. It was created almost a century before the Franco-Prussian War and Germany itself. By the time of hostility between France and Germany, the name was already quite traditional.
I don't know if there was much controversy over use of French during World War I, but the fact that the name is of a much older vintage than Germany itself may have contributed to a lack of impetus to rename it among the prussian military elite.