It would certainly be an atrocity, if that’s what you’re getting at. There is no less value to Palestinian or Native American lives than to European ones. Genocide, however, is the systematic persecution with the intent to eliminate a certain ethnic group.

The difficulty in your example arises with defining that “genus” in the modern sense of genocide, since “Parisian” is a very diverse mix of people. What makes them “Parisian”?

If their common association is, say, having their primary residence in Paris, or having been in Paris during a certain point or stretch in time, I suppose we could coin the term “urbicide”, but I don’t know if there’s a historical precedent for the systematic persecution of a specific city by whatever definition.

There is the historic phenomenon of soldiers wantonly slaughtering a chunk of the populace of a captured city, but if you wanted to actually use the administrative and productive value of that city you’d want to keep the killing in check. On the other hand, raiding other tribes or villages and killing inhabitants with the purpose of driving them away from your lands also involved the murder of civilians, but the intent was foremost to secure resources and prosperous land for your own people.

Failing any other classification, it would still be a massacre. We don’t need to slap particularly loaded labels onto everything bad to make it bad. Doing so dilutes the meaning of those terms, watering down both their political weight and their usefulness in classifying events.