Short answers, pulled from the story.
French Emperor Napoleon Bonaparte signed the Treaty of Tilsit with Prussia to create the Duchy of Warsaw. This agreement transferred ethnically Polish lands from Prussia to France for the first time since the late 18th century partitions.
The Duchy of Warsaw existed as a French satellite state from 1807 until 1815. Most territory was occupied by Russia in January 1813, and formal dissolution occurred at the Congress of Vienna in 1815.
Following the annexation of West Galicia in 1809, the population increased to roughly 4,300,000 people. By 1810 the duchy had a population of 4,334,000 of whom 79% were ethnic Poles.
When Napoleon launched his invasion of Russia in 1812 the army totaled almost 120,000 troops out of a total population of just 4.3 million people. Prince Józef Poniatowski served as Commander in Chief of this force from 1807 until 1815.
The French Empire imposed an agreement at Bayonne requiring the duchy to buy debts owed by Prussia amounting to more than 43 million francs. Heavy drain on resources from forced military recruitment combined with drops in grain exports caused significant inflation and over-taxation throughout the economy.