First of all the citizens were divided as Active citizens- who can vote and passive citizens, who cannot. Only men of 25 years of age who paid taxes were given the status of active citizens. Rest were passive.
The active citizens voted for a judge and electors(50000 men) who in turn voted fro the national assembly(745 members).
Electors and National assembly constituted the Legislature.
Now the national assembly controlled the actions of the king and ministers who constituted the Executive.
Judge constituted the Judiciary.
Also, king had the veto power, a power to dissolve the national assembly.