Old French Holiday

/r/ for some Frenchy info. When France lost Alsace-Lorraine to Germany after the Franco-Prussian war, they created a national holiday to commemorate its loss. I can't find the name, wiki doesn't have any mentions, googling isn't turning up much. Anyone heard of this before?

La fête nationale est instaurée en 1880, est-ce que c'est ce dont vous parlez? Le contexte revanchard de l'époque peut certainement avoir accéléré son instauration