Events from the year 1808 in France.

• Emperor – Napoleon I^[1]

• 22 January – The Bragança Portuguese Royal Family arrives in Brazil, having fled the French army.
• 2 February – French troops occupy Papal States (Vatican).
• February – Under the pretext of reinforcing the Franco-Spanish army occupying Portugal, French troops begin filing into Spain.
• 29 February – A French column, disguised as a convoy of wounded, takes Barcelona by convincing the authorities to open the city's gates.
• 23 March – Madrid is occupied by French forces.
• 2 May – Dos de Mayo Uprising, the people of Madrid rebel against the occupation of the city by French troops, provoking a brutal repression by the French.
• 5 May – Napoleon forces the Spanish royal family to abdicate and hands the throne to his brother Joseph.
• 25 May – Asturias rises up in arms, casting out its French governor.
• 17 April – Bayonne decree, ordering the seizure of American vessels in France.
• 4 June – Peninsular War: Battle of El Bruc, Spanish victory over French forces.
• 12 June – Peninsular War: Battle of Cabezón, decisive French victory over Spanish forces.
• 15 June – Peninsular War: Siege of Saragossa begins, as French forces repeatedly attack the city.
• 14 July – Peninsular War: Battle of Medina del Rio Seco, crushing defeat of Spanish army by the French.
• 18–22 July – Peninsular War: Battle of Bailén, Spanish forces surround the French and compel the surrender of almost 18,000 men. It was the worst disaster suffered by the French during the Iberian campaign.
• 30 July – Peninsular War: French forces massacre the population of Évora.
• 13 August – Peninsular War: Siege of Saragossa ends in defeat for the French who were forced to lift the siege and retreat.
• 17 August – Peninsular War: Battle of Roliça, British victory over the French, first battle fought by the British army during the war.
• 20 August – Peninsular War: Battle of Vimeiro, Anglo-Portuguese victory over French forces.
• 30 August – Peninsular War: Convention of Sintra signed, by which the defeated French are allowed to evacuate their troops from Portugal without further conflict.
• 27 September – Congress of Erfurt, between Emperor Napoleon I and Tsar Alexander I begins.
• 14 October – Congress of Erfurt ends.
• 31 October – Peninsular War: Battle of Zornoza, indecisive battle between French and Spanish forces.
• 4 November – Napoleon creates the département of Tarn-et-Garonne.
• 5 November – Peninsular War: Battle of Valmaseda, Spanish victory over French forces.
• 7 November – Peninsular War: Battle of Burgos, French victory over Spanish forces.
• 10–11 November – Peninsular War: Battle of Espinosa, French victory over Spanish forces.
• 23 November – Peninsular War: Battle of Tudela, French victory over Spanish forces.
• 30 November – Peninsular War: Battle of Somosierra, outnumbered Spanish force fails to prevent Napoleon from moving on Madrid.
• 1 December – Peninsular War: French patrols reach the outskirts of Madrid.
• 4 December – Peninsular War: Madrid surrenders and French enter the city for the second time that year.
• 21 December – Peninsular War: Battle of Sahagún, British victory over French forces.

• 1 April – Jean-Baptiste Dubois de Jancigny, French agronomist and scientist (born 1753)
• 26 April – Jean-Baptiste Pillement, painter and designer (born 1728)
• 30 May – Louis-Charles, Count of Beaujolais, younger brother of King Louis-Philippe I of the French (born 1779)
• 10 June – Jean-Baptiste de Belloy, Archbishop of Paris and Cardinal (born 1709)
• 17 June – Louis-Joseph de Laval-Montmorency, Cardinal (born 1724)
• 23 July – François-Hippolyte Barthélémon, composer and violinist (born 1741)
• 6 September – Louis-Pierre Anquetil, historian (born 1723)