From Wikipedia:
On
December 11 and December 12 (Old Style) 1602 — the longest night
of the year — the forces of the Duke of Savoy, under the command
of the seigneur d'Albigny, and those of Charles Emmanuel's
brother-in-law, Philip III of Spain, launched an attack on the
city-state of Geneva. The troops marched along the Arve River at
night and assembled at Plainpalais, just outside the walls of
Geneva, at 2 o'clock in the morning. The original plan was to
send in a group of commandos to open the gate door and let the
other troops in. The Geneva citizens defeated the men by
preventing them from scaling the wall (a climb in French is an
escalade). The night guard Isaac Mercier raised the alarm,
church bells were rung, and the Genevois were alerted. The
populace fought alongside their town militia. The duke's
2000-plus mercenaries were beaten. The Genevois lost 18 men in
the fighting; the Savoyards suffered 54 fatalities and the
troops had to retreat. Thirteen invaders who had been taken
prisoner, including several well-born gentlemen, were summarily
hanged the following day as thieves, since they could not be
treated as prisoners of war, peace having been repeatedly sworn
on the part of Savoy.