Ravaillac had followed the coach from the Louvre, had seen it stop and noted that there was now no one near it and no one to interfere with him as he came close to the side of the carriage where the King was seated. Ravaillac had his cloak wrapped round his left arm to conceal a knife and creeping in between the shops and the coach as if he desired to pass by, paused there, and resting one foot upon a spoke of the wheel, the other upon a stone, leaned forward and stabbed the King. The knife entered a little above the heart between the third and fourth ribs. The King, who was reading a letter, fell over towards the Duc d'Épernon on his other side, murmuring, "I am wounded." At this moment Ravaillac, fearing that the point of his weapon had been turned aside, quickly struck a second blow at the fainting monarch, who had raised his arm slightly, thus giving the knife better chance to reach his heart. This second stroke was instantly fatal. The blood gushed from his mouth and he expired breathing a deep sigh. His Majesty's attendants, now running up, would have killed Ravaillac on the spot, but the Duc d'Épernon called out to them to secure his person, whereupon one seized the dagger, another his throat, and he was promptly handed over to the guards. The news spread that the King was dead and caused a panic. People rushed from the shops into the streets and a tumult arose which was stayed only by the prompt assurance of d'Épernon that the King had merely fainted and was being carried to the Louvre for medical attention.
The murder created intense excitement in the city, for the King was beloved and trusted by the people as the one hope of peace after such constant strife. Sully, his faithful minister, was broken-hearted but acted with great promptitude and firmness. He brought troops forthwith into Paris and strengthened the garrison with the Swiss guards. Despair and consternation prevailed in the Louvre, where were the widowed Queen, Marie de Medicis, and the infant heir, now Louis XIII. Bassompierre, in his memoirs, tells us how he found the dead King laid out in his cabinet, surrounded by afflicted followers and weeping surgeons. Summoned to the Queen's presence, he found her in dishabille, overcome with grief, and he with others knelt to kiss her hand and assure her of his devotion. The Duc de Villeroi reasoned with her, imploring her to postpone her lamentations until she had made provision for her own and her son's safety. While the Duc de Guise was directed to bring together all the principal people to recognise and proclaim the new sovereign, the marshal proceeded to gather up all the troops and march through the city to check any signs of tumult and sedition. Meanwhile, Sully had occupied the Bastile with a force of archers and had enjoined all good subjects to swear allegiance to the throne and proclaim their readiness to give their lives to avenge Henry's murder.