Bay Area history teacher was suspended from teaching on Thursday over a lesson in which he examined parallels between the rise of Trump and German Nazi dictator Adolf Hitler.

The Monterey Herald said that Mountain View High School placed teacher Frank Navarro on paid leave after a parent complained in an email about the lesson and statements that Navarro made in class.

Navarro — a 40-year classroom veteran and expert in Holocaust studies — said, “This feels like we’re trying to squash free speech. Everything I talk about is factually based. They can go and check it out. It’s not propaganda or bias if it’s based on hard facts.”