I can speak to the government of Napoleon I, which I’ll paraphrase from another response where I compared Napoleon’s government to the constitutional monarchy of 1791 here

The First French Empire was a monarchy hidden under the thinnest veneer of democracy, and certainly was not anything close to a republic like the Directory or what was described in the constitution of 1793. Even the constitutional monarchy of 1791 was much more democratic than Napoleon’s regime. Napoleon I ruled under three different constitutions throughout his reign, with each becoming more authoritative than the last. For argument’s sake, let’s focus on the Constitution of Year VIII (1799), which was the first and most democratic of the three.

While it was approved by a popular plebiscite vote, that is where the democratic process ends. At the top, three “Consuls” ruled as executives, with Napoleon being the most powerful prominent First Consul. These were supposed to be elected positions, but the constitution simply decrees that the office will first be filled by Napoleon and his two goons. There are no term limits, naturally. Being the first consul came with all sorts of fun powers, including but not limited to: the power to unilaterally arrest anyone, the sole power to declare war, sole control of the treasury, exclusive control over all foregn relations, the power to appoint or dismiss any member of the bureaucracy, etc. See pg. 275 of the linked text for more.

There were two legislative bodies, known as the Tribunal and the Senate, respectively. The Second and Third Consuls, who were entirely subordinate to Napoleon, directly appointed members of both the Senate and the Tribunal, the two legislative bodies. The names the Senators were also kept from the public to keep the public from influencing their representatives. Laws could not be introduced in either chamber, rather the First Consul had to personally propose all legislation. The Tribunal could debate legislation and the Senate could vote on it, but neither could do both. All amendments and final laws had to be approved by the First Consul. Furthermore, the First Consul had the ability to seize all meaningful power that wasn't already at his fingertips whenever he pleased.

Napoleon essentially held all the power in government, and there was very little his government could legally do to oppose him.

For a complete translation of all the constitutions of the French Revolution and Napoleonic era, see this helpful digitized book.