It wasn't only NB who felt strongly about Dupont's capitulation. Napier:

" Thus, above eighteen thousand French soldiers laid down their arms on the 22nd, before a raw army incapable of resisting half that number if the latter had been lead by an able man ... disgraceful affair ... folly and fear ... shameful ... It must be confessed that Dupont, unless a worse explanation can be given of his conduct, was incapable to the last degree. ... Joseph called Dupont's capitulation a 'defection;' perhaps he was right."

Not that NB got his opinions from Napier, but he was not the only one at the time to feel that Dupont had done unacceptably badly. And at Fontainebleau perhaps a suspicion, as Napier seems to be hinting, that Dupont was bribed, or promised a bribe, to capitulate?