What is the meaning of Commissionaire?

One entrusted with a (small) commission, such as an errand; especially, an attendant or subordinate employee in a public office, hotel, etc.

A uniformed doorman.

An undisclosed agent under European civil law.

Jespersen, Otto (1909) A Modern English Grammar on Historical Principles (Sammlung germanischer Elementar- und Handbücher; 9), volumes I: Sounds and Spellings, London: George Allen & Unwin, published 1961, § 12.22, page 342.

Source: wiktionary.org