"Life was better under Franco" has become a trope on social media, hooking a frustrated generation that has received little education on the dictatorship and is receptive to anti-system politics.

After overthrowing a democratic republic in a 1936-1939 civil war that killed hundreds of thousands of people, Franco ruled Spain with an iron fist until his death in 1975.

But Cristina Luz Garcia, who teaches history at a Madrid school, said she has seen some of her students repeat "myths" and "phrases that are closely tied to the regime itself and Francoist propaganda".

Those pupils do not have "very deep knowledge of the person" or of "the negative consequences" of 36 years marked by torture and the denial of freedoms, she told AFP.

The pro-Franco narrative is, for some students, "a way to defy the teachers or appear to have a different opinion... which is something very attractive about adolescence itself", she added.