I often hear people use the word "indeed" in a response to someone sharing an idea and suggesting the fact that they already knew or thought about the idea. Almost as a substitute to "Obviously", but in a more passive way. Therefore suggesting that they are already miles ahead and causing that condescending tone.
Its translation in french on the other hand has a more polite connotation. It suggests an agreement and often the idea that the receiver didn't think about it beforehand.
I'm not a native english speaker and I would like to avoid conflicts and clarify if this word has a condescending meaning in its popular use.