https://en.wikipedia.org/wiki/Massacre_of_the_Latins
which was a reaction to the empire becoming near completely dominated by westerns both economically and (to a lesser degree) politically.
The last coup attempt/civil war (which was also a near permanent issue in the empire) before the massacre was between a French Princess ruling the empire as a regent for her underage son and her stepdaughter who was married to a Frankish nobleman from the Outremer (he was -the second highest ranking official in the empire and seemingly the heir apparent together with his wife). Had they succeeded the Empire would probably have had its first Latin Emperor (or at least co-Emperor) without even being directly conquered. Of course instead it ended with late emperor's cousin* murdering (he forced the 12 year old emperor to sign her mothers death warrant and before having him assassinated soon after). mothers everyone and taking the throne for himself after he masterfully utilized the widespread public hatred towards the Latins amongst the general population..
*Andronikos Komnenos, who was in his middle 60s at the time and while being quite a terrible person had a very interesting life. Amongst other things (while in exile due all kinds of scheming) he seduced the former queen of Jerusalem (who happened to be his niece..) and up having two children with her after they ran away to the Turkish Sultanate of Damascus. Eventually she was captured by the emperor who used her to lure Andronikos into Constantinople and then (unfortunately for the emperor's son) decided pardon him and exile him to a remote province instead of executing him.
