The Federal Assembly is, politically speaking, not made up of parties, but rather divided into groups or factions. The factions comprise the members of the same party or of similarly-platformed parties. A parliamentary faction is therefore not necessarily to be equated with a party.

At least five deputies of a Council must band together in order for a faction to be formed.

The parliamentary groups play an essential role in forming opinions. They examine the main issues (elections and current issues) before they are submitted to the Councils and attempt to reach a common viewpoint, which the members of parliament can defend before their Council as well as the media and the general public. In the National Council, a member of parliament has to be in a group to be on a committee.

• Statistics regarding factions, since 1912 (XLS)
• Factions which do not exist today