Did Napoleon say he had 'given England a rival' by selling Louisiana to the US?
TL;DR I've hit a dead end in my search for the origins of a quote attributed to Napoleon about the Louisiana purchase, and would greatly appreciate any information on its origin and context.
I recently came across a Reddit post which claimed that, upon approving the Louisiana purchase, Napoleon stated 'I have given England a rival who, sooner or later, will humble her pride'. This seemed a remarkably confident/prescient statement for 1803 (not that Napoleon was noted for a lack of confidence, of course), so I went digging to find the context of this quote.
The phrase has gone through a lot of permutations over the years, but I've found French and English versions from the 1880s that more or less agree on its substance:
>This accession of territory strengthens forever the power of the United States; and I have just given to England a maritime rival that will sooner or later humble her pride
James Parton, Life of Thomas Jefferson, Third President of the United States (1883)
>Elle assure à jamais la puissance maritime des États-Unis. En agissant comme je l’ai fait, j’ai suscité à l’Angleterre une rivale qui, tôt au [sic] tard, lui ravira le sceptre des mers et humiliera son orgueil.
Charles de Varigny, Les Grandes Fortunes en Angleterre (1889)
Unfortunately, both Parton and de Varigny are more interested in telling a good story than in historiographical exactitude and fail to mention their source, so I seem to have hit a dead end.
Can anyone shed any light on the origins and context of this quote, or point me to an earlier appearance of some version of it than the two mentioned above?