Okay, here’s that guide to how open your Renault 4CV sunroof should be in various situations you wanted. To recap, windmills:closed, traffic: half-open, rural areas: NO SUNROOF, shipyards: half, and mountain ranges: full. Please commit this to memory so we can avoid any unfortunate incidents.
Senior Editor, Jalopnik • Running: 1973 VW Beetle, 2006 Scion xB, 1990 Nissan Pao, 1991 Yugo GV Plus, 2020 Changli EV • Not-so-running: 1977 Dodge Tioga RV (also, buy my book!: https://rb.gy/udnqhh)
Most 4CV families owned two cars, in order to have one that was suitable for all areas. Early on, some people attempted to enter the countryside after filling the seams around their closed sunroof with toothpaste as a temporary caulking, but that stopped after the first time a family was caught in a rainstorm while racing back to town. I won’t go into detail as to what happened, but I’ve seen the news articles from that time and I will say that I was surprised by how graphic they were, even for the French.