Short answers, pulled from the story.
The Sénat conservateur was an advisory body established in France in 1799 under the Constitution of the Year VIII, following the Coup of 18 Brumaire. Its stated purpose was to watch over the survival of the constitution, not to exercise ordinary legislative powers.
The Sénat conservateur was established on the 13th of December 1799 under the Constitution of 22 frimaire Year VIII. It lasted until 1814, when Napoleon Bonaparte was overthrown and Louis XVIII abolished the body after the Bourbon monarchy was restored.
A sénatus-consulte was an act issued by the Sénat conservateur carrying the force of law, used for matters the constitution did not address. Napoleon used sénatus-consultes to grant amnesty to émigrés in 1802, proclaim himself First Consul for life, reestablish the Gregorian calendar in 1805, and reshape the empire's territorial boundaries.
Senators were not elected. The original Constitution named Sieyès and Roger Ducos as members by right and allowed the outgoing and incoming consuls to choose 29 additional senators. That majority then chose the remaining members. Napoleon personally designated candidates from electoral college lists and could also name senators on his own initiative.
In January 1803 Napoleon created the sénatoreries, grants that gave 36 senators the lifetime right to a residential palace and an annual revenue of 20,000 to 25,000 francs, roughly double ordinary senatorial pay. For example, the chemist Berthollet received the sénatorerie of Montpellier, occupied the bishop's palace at Narbonne, and received 22,690 francs a year.
The Sénat conservateur met at the Luxembourg Palace in Paris. The architect Chalgrin fitted a semicircle of seats into the central part of the building to accommodate the chamber. The Constitution specified that sittings were not to be public.