-- of course, this was the 1500s, remember? you support the losing side in a political battle (like the Huguenots did in France, the Catholics in the UK), you die.
What they hadn't done was subdue Paris. So, when a bunch of Huguenots showed up the Mob was easily riled up.
You ever visit those palaces over on the Loire? The Parisian Mob was one of the reasons why the nobles and royals kept places SOMEWHERE ELSE.
The deGuise family (as distinct from the Guise faction) kept a series of palaces in Provence ~ where it was safer, and where there were more Huguenots. You can imagine how Italian history might have progressed if France had still had it's Huguenots to "kind of guide things along the border".