Well, sort of.

The Estates-General (Reichsstände) were indeed initially intended to have some sort of override power, even on bills dealing with the budget and state finance. The king had to submit certain types of legislation to them, and they could theoretically vote "No."

In their 1808 session, of the 10 bills they voted on, six had to do with taxes, finance, or the budget.

Then things got interesting when the law for the property tax was defeated, 61-24. Some furious behind-the-scenes negotiating took place with prominent delegates and royal cabinet members, while Malchus harangued the recalcitrant delegates both verbally (a three-hour speech! ugh) and in the official Moniteur. The law was re-crafted to make it more attractive to large landholders, and it passed on the very last day of that year's session, 18 August, 1808.

(They didn't have the safeguard that Napoleon did in France, where any number of "Yes" votes could approve a measure, but 60% "No" votes were required to defeat it. In fact, I'm not aware of any instances when Napoleon's legislature said "No" to him, but I would be happy to be corrected about that.)

The Westphalian Constitution required the Reichsstände to meet annually, but they only met twice. They missed the 1809 session because of all the rebellions. And then they met for the last time in 1810, and again voted "No" on one of the tax bills (a new stamp tax). This time Jerome didn't bother trying to negotiate. He just overruled them and ignored the result. He never called them into session again, and ruled by decree, which was unconstitutional, but... Oh Well.

Just to be clear: this was not a popularly-elected legislature like the US House of Representatives. The Cabinet (Staatsrat) set the parameters on membership by class. (There had to be 70 landowners, 15 merchants, and so on.) Would-be candidates had to be approved first by the central gov't, and then could "campaign" within their respective prefectures, but in each department there were only 200 electors who could vote for them. I read a memo from the Interior Ministry in early 1808, by which "troublesome" candidates were weeded-out. That typically meant: anybody suspected of loyalty to the Old Regime states.