James Monroe had sailed for Paris on…
March 1803 CE
Their instructions are to negotiate, or possibly purchase, control of New Orleans and its environs; they do not anticipate the much larger acquisition that will follow.
Napoleon needs peace with the United Kingdom to implement the Treaty of San Ildefonso and take possession of Louisiana.
Otherwise, Louisiana will be an easy prey for the UK or even for the United States. But in early 1803, continuing war between France and the UK seem unavoidable.
On March 11, 1803, Napoleon begins preparing to invade the UK.