Here is a proposal for the French Empire of the CS-1 timeline in which Napoleon Bonaparte's First French Empire survives to the present day.
18 May 1804 - French Senate declares Napoleon Bonaparte Emperor of France.
1805 - Napoleon begins to re-organize the German states and re-establishes the Grand Duchy of Luxemburg making himself the Grand Duke.
1806 - Emperor Franz II of the Holy Roman Empire abdicates his title as Holy Roman Emperor and Napoleon I is officially crowned Emperor twice in a double coronation. On 6 August 1806, Napoleon becomes both the Emperor of France and the Holy Roman Emperor by the crowning of Pope Pius VII. Unlike in OTL... the Holy Roman Emperor is not abolished and Napoleon retains the title of Roman Emperor until his death in 1821.
1815 - Napoleon instigates a Congress of Vienna to affirm his authority over the French and Holy Roman Empires ensuring the survival of his nation.
5 May 1821 - Napoleon I dies and is succeeded by his son Napoleon II.
1832 - Napoleon II dies and is succeeded by Napoleon III.
About 1860 - Napoleon III begins to work on his plan for the re-shaping and influence of Latin America.
1862 - The Second Mexican Empire established under Maximillian I.
22 November 1862 - With the help of the Napoleon III and his alliance with Mexico and the United Kingdom... the Confederate States of America is established following a Southern Victory in the War of Secession.
1870 - Napoleon III dies and is succeeded by Napoleon IV.
1871 - Napoleon IV is ousted as Holy Roman Emperor marking the end of Bonaparte rule over the Holy Roman Empire of the German Nation and marking the start of Prussian rule over the HRE beginning with Wilheim I.
1906 - Napoleon IV and the Bonaparte dynasty celebrate 100 years of Bonaparte rule in France.
1914 - World War I begins with the alliances of France, the UK and the CSA against the United States and the Holy Roman Empire under Kaiser Wilheim II.
1918 - The Central Powers (The United States, Austria and the Holy Roman Empire) defeat France, the United Kingdom and the Confederate States in World War I resulting in loss of territory by the French Empire and a movement to oust the French Emperor from power.
1919 - Napoleon IV dies and the French Imperial throne sits vacant in the midst of a civil war between the Imperialists and the Republicans who support turning the French Empire into a republic.
1921 - Monarchist forces win the civil war and Napoleon V is crowned the new Emperor of France.
1941 - Second World War started by France and the CSA in attempt to regain lost territory from the previous war.
1946 - The United States, Austria and the Holy Roman Empire once again defeat the Alliance of France, the United Kingdom and the Confederate States in the Second World War which results in the impeachment of the Confederate States President as well as the abdication of Napoleon V in favor of his son.
This is incomplete..
List of Emperors of the French Empire
Napoleon I (1806-1821)
Napoleon II (1821-1832)
Napoleon III (1832-1870)
Napoleon IV (1870-1919)
- Imperial throne vacant due to civil war from 1919 - 1921.
Napoleon V (1921-1946)
Napoleon VI (1946-1985)
Napoleon VII (1985- )