Gigachad:

What's the reason for the flags of Romania and Chad being basically the same?

There's no story, i think it's just one of those weird coincidences. I know that the romanian flag had the same layout as far back as the 19th century and possibly earlier, so it predates Chad's, who got their independence ( and presumanly their flag ) in the 60s.

During the communist regime however (1948-1989) Romania's flag also had an emblem in the middle, so when Chad decided on their flag i assume they chose the simple blue-yellow-red because it wasn't technically "taken".

After the revolution we ( Romania ) reverted to the simple flag, which was now conflicting with Chad's.

Edit: additional fun facts - during the early 90s there weren't a lot of "new" flags in Romania, so we used the communist ones but with a hole where the communist emblem used to be. That's why pretty much all the flags you see in images with Romania during that time will have holes in them. The cut flag was also a symbol of the revolution for a good while.