By the time right before WW1, A-L was fading as an issue.
It had seemed to be fading, if only because many of the people of Alsace-Lorraine did not care for the anticlerical direction the French Republic was taking after the Dreyfus Affair. But then came the Zabern affair.
https://en.wikipedia.org/wiki/Zabern_Affair https://groups.google.com/d/msg/soc.history.what-if/13xS3xMHyvM/WbhIvteb9mMJ
Nationalism was actually undergoing something of a revival in France, which threatened to revive the issue of Alsace-Lorraine. "The public, too,
at least until the nationalist revival in the years immediately before 1914 , seems to have been largely unenthusiastic, indeed apprehensive, about the prospect of another war even for Alsace and Lorraine." [emphasis added--DT]
https://books.google.com/books?id=xjLz2685I74C&pg=PT223 "
"[In the Latin] Quarter 3,000 demonstrated, chanting "Vive I'Alsace! Vive la Lorraine!" and in the Parisian theaters patriotic plays were newly popular. From the countryside observers noted a new belligerence among peasant farmers.. Joan of Arc, who had been beatified in 1909, enjoyed a fresh popularity. This time the enemy was not the British, however. "Wilma says that in her circles everyone is mad for war," Harry Kessler reported in 1912 of his sister who lived in Paris. "All are convinced that they will beat us."39 When a German Zeppelin had to make a forced landing in a French town in the spring of 1913, local crowds threw stones at the crew. The French government apologized for the "lamentable" behavior. Wilhelm wrote an angry note: "this is really mild! It is simply plebeian and uncivilised, like in a land of barbarians! This is derived from anti-German agitation!". The Zabern affair a few months later, when German officers treated the inhabitants of Alsace with contempt, received wide coverage in the French press which saw it as yet another example of Prussian militarism.41 (Moltke found the belligerence in the French press useful as a further justification for increasing the size of the German army.)42"
https://books.google.com/books?id=xjLz2685I74C&pg=PT674
It's tempting to think that the longer the time since 1871, the less Alsace-Lorraine would matter, but history does not necessarily work in that straightline-progressive fashion. See Eugene Weber's
The Nationalist Revival in France, 1905-1914. Speaking of the years just before the War, "National sentiment had become lively, almost irritable. The words "Alsace-Lorraine" would be greeted with cheers in the schools, and lecturers now hardly dared to mention German methods or ideas for fear of the murmurs and catcalls.."
https://books.google.com/books?id=nbD8_7npgOwC&pg=PA107