- 3 May
- 1804 : Adoption by the Tribunes, with one vote against, of the motion to raise Napoleon Bonaparte dignity to the one of Emperor of the French.
- 1811 : Massena's victory over Wellington at Fuentes de Oñoro.
- 1814 : Arrival of Napoleon at Elba. Entry of Louis XVIII in Paris.
- 4 May
- 1802 : Filing of a bill establishing the Legion of Honor.
- 1807 : Signing of a pact of friendship between France and Persia, at Finckenstein.
- 1810 : Birth of Alexandre Walewski, the illegitimate son of Napoleon and Maria Walewska.
- 1814 : Landing of Napoleon to Elba.
- 5 May
- 1808 : Interview of Bayonne. The Spanish crown is placed at the disposal of Napoleon.
- 1812 : The Emperor leaves Paris. He shall not see it again until March 21, 1815.
- 1821 : Death of Napoleon.
- 6 May
- 1805 : Reconciliation of Napoleon and his brother Jerome, who agrees to divorce.
- 7 May
- 1796 : Entry of Bonaparte at Piacenza.
- 8 May
- 1801 : In Saint-Domingue, Toussaint Louverture enacts a constitution.
- 1802 : Extension of ten years of the mandate of the First Consul. A Senator proposes that Bonaparte gets this dignity for the rest of his life.
- 1805 : Villeneuve and his fleet arrive in Martinique but fail to operate their junction with that of Rochefort, commanded by Missiessy.
- 9 May
- 1796 : Signing of a truce with the Duke of Parma.
- 10 May
- 1796 : Victory of Lodi. Bonaparte is promoted to corporal by his soldiers.
- 1806 : University Foundation.
- 1811 : Massena is replaced by Marmont at the head of the army of Portugal.
- 11 May
- 1803 : France rejects the British ultimatum demanding the evacuation of Holland and approval of the British presence in Malta.
- 1809 : Installation of Napoleon at Schoenbrunn Palace.
- 12 May
- 1802 : The consulate for life is passed unanimously minus the voice of Carnot in Tribunate, unanimously minus three votes in the Body legislature.
- 1803 : Out of the Treaty of Amiens.
- 1814 : Twelve thousand officers, declared supporters of Napoleon, are set half-pay.
- 13 May
- 1801 : Cutting of the Cisalpine Republic in twelve departments.
- 1809 : Signature of the capitulation of Vienna.
- 1814 : Ferdinand VII comes back in Madrid. He instantly reinstalls the Inquisition and absolute monarchy.
- 14 May
- 1802 : Amnesty for the crimes of desertion committed in France by soldiers of the French troops.
- 15 May
- 1779 : Admission of Bonaparte at the military school of Brienne.
- 1796 : Entry of Bonaparte in Milan.
- 1797 : Occupation of Venice. Leak of the Doge.
- 1815 : Royalist rebellion in the Vendee.
- 16 May
- 1797 : Signing of a peace treaty with Venice.
- 1806 : The British government decides to blockade the coast and ports, from the Elbe to Brest.
- 1811 : Soult is defeated at the Albuera by an army Anglo-Hispano-Portuguese.
- 17 May
- 1799 : Lifting of the siege of Saint Jean d'Acre.
- 1809 : Meeting of the Papal States to the French Empire.
- 18 May
- 1802 : The purchase of a replacement by the conscript becomes legal.
- 1804 : A Senatus-consultum who proclaims Napoleon Bonaparte Emperor of the French is approved unanimously least three votes.
- 19 May
- 1798 : Departure for Egypt.
- 1802 : Adoption of the bill establishing the Legion of Honor.
- 1804 : Appointment of fourteen marshals of the Empire: Berthier, Murat, Moncey Jourdan, Massena, Augereau, Bernadotte, Soult, Brune, Lannes, Mortier, Ney, Davoust, Bessieres, and of four marshals-Senators: Kellermann, Lefebvre, Perignon, Serrurier.
- 20 May
- 1800 : Passage of the col of Saint-Bernard.
- 1802 : Reinstating of the slave trade. Slavery is re-established in the French colonies.
- 22 May
- 1809 : Second day of the Battle of Essling. Fatal injury of Marshal Lannes.
- 1813 : Death of Duroc.
- 23 May
- 1803 : Declaration of war against England.
- 1808 : Beginning of the Spanish insurrection.
- 1809 : Failure of an attack against the Emperor at Regensburg.
- 24 May
- 1806 : Removing of the republican regime in Holland.
- 1808 : The Duchies of Parma, Piacenza and Tuscany are united to Empire.
- 25 May
- 1804 : Starting of the trial of Cadoudal, Moreau and their forty-five co-defendants.
- 26 May
- 1796 : Taken of Pavia.
- 1805 : Coronation of Napoleon as King of Italy in the Cathedral of Milan.
- 1807 : The Marshal Lefebvre gets the capitulation of Danzig.
- 27 May
- 1796 : Entry in Brescia.
- 1799 : Second visit to the plague victims of Jaffa.
- 1803 : Invasion of Hanover by Mortier.
- 1808 : Anti-French protests in Valencia. Four hundred French are killed.
- 1814 : Davout evacuates Hamburg.
- 28 May
- 1808 : Uprising of the people of Cadiz.
- 29 May
- 1802 : Adoption of the act of Malmaison by an assembly of notables Swiss.
- 1814 : Death of Josephine at Malmaison.