Yesterday, I investigated the French state of siege. This is the emergency weapon in France and variations of it appear in other countries. For example, the state of emergency in Germany up to at least WWIi was largely based on it. The state of siege can be thought of as being similar to martial law.
The state of siege (there’s something very Steven Segal about it!!) was part of a triumvirate initially; there was a state of war and a state of peace, they were designated not long after the French Revolution. None of them were real emergency weapons. There was, in principle, no suspension of the constitution of concentration of powers. Much of the heavy-handed stuff was done by Commissars affiliated with the National Convention.
The state of siege begin a strange odyssey. It became a fictitious instrument, a political football. Before, it was applied to specifically military scenarios. Then it took a back seat as an emergency instrument from about 1800 – 1849. Between 1815-1830 there were no dictatorial powers because the monarchy was effectively absolute. 1848 precipitated the state of siege being developed into a means of instituting crisis powers. With a few modifications, a law of 1849 basically regulates French emergencies.