Its foundation

The Constitution du 22 Frimaire an VIII (13 December, 1799) established government by three consuls appointed for a ten-year term of office. A consultative body, the Conseil d'Etat, was attached to them (art. 52-53), and its members were appointed and could be removed from office by the First Consul. This body was responsible for drawing up bills, the system of public administration and for resolving administrative disputes, under the direction of the Consuls.
The idea undoubtedly originated with Sieyès and was adopted by Bonaparte.
On 3 Nivôse Year VIII (24 December, 1799), at an unofficial meeting, the First Consul received the new conseillers d'Etat and swore them in individually. Bonaparte appointed twenty nine conseillers to five sections (Législation (legislation), Intérieur (domestic affairs), Finances (finance), Guerre (war) and Marine (navy)). On the same day he nominated the presidents of each section. (13 décembre 1799)

Roederer describes this session in his Mémoires :
" [Bonaparte] said to me: "Do not accept your nomination [to the Senate]. What good would you do there? You should go into the Conseil d'Etat. That is where there are great things to be done. It is from there that I shall choose my ambassadors and ministers."
Thus the Conseil d'Etat came into being. Those that were to be its members were invited to the Palais du Luxembourg, into a room in the First Consul's apartment. At around five o'clock they were ushered in one by one. After taking the oath, each one took his seat."

The Government was officially installed at the Palais du Luxembourg on 4 Nivôse, An VIII (25 December, 1799), and the first general assembly of the Conseil d'Etat was then held. On 5 Nivôse (26 December,1799), its first ruling, which owed a great deal to Cambacérès, Boulay and Roederer, established the internal organisation and remit of the Conseil.

Its first task was to restore civil harmony

The Conseil d'Etat and the Consuls quickly embarked on the task of restoring public order. The Consuls' call for harmony declared that "the Conseil d'Etat is working assiduously to prepare the reform of bad laws and to create a more appropriate arrangement of public taxation". The Conseil d'Etat met every day.
On 6 Nivôse (27 December, 1799) the restrictions imposed on the nobility and relations of immigrants were repealed. On the 7th, three consular orders, "having regard to the opinion of the Conseil d'Etat", eased the restrictions on freedom of worship.
The law of 28 Pluviôse, An VIII (17 February, 1800), drawn up by the Conseil, reorganised local government.

From 5 Nivôse to 30 Pluviôse, An VIII, in the fifty days between the first session of the Conseil in the Petit Luxembourg and its move to the Palais des Tuileries, 201 matters had already been referred to the Conseil.