Check out this link http://www.bruxelles.be/artdet.cfm/4445
The article is in French so I will endeavor to expound in English.
Only a portion of the records is online as of yet: the City's "Livres d’Or" (golden Books), some Commerce and Industry Almanacs, and "Cahiers bruxellois".
The Golden Books
These dignitaries were, for the most part, heads of state and foreign officials, invited by the burgomaster, but also included honored guests such as prominent artists or sports personalities. This signing usually takes place in the burgomaster's office at the start of the meeting and is often accompanied by a photo session.
These golden books are leather-bound and bear the city's symbol on the cover page: St Michael. These books are kept by the Protocol service and later kept in the city Archives.
Three of them are accessible online. The first one covers the period of 1843 to 1967. The second one covers the years between 1967 and 1999. The pages of the third one have been scanned up to November 2010.
The online viewing enables easy access to the history of the City of Brussels.
Click on your choice of Book 1, 2 or 3. Another page will open from which you will be able to navigate by thumbing through the book, that is, simply turning the page. Zoom in if the picture is not clear, pan it to move it around, print it if you like.
Note that due to a problem with the binding of the first book, the first 10 pages are off center.
They make it possible to put together lists of building renters or owners, to locate the movement of someone within the city or in the suburbs and even note the eventual job promotions or changes. When used in combination with the population registers these lists can be very useful for the researcher as personal circumstances could change very rapidly.
These books can no longer be handled manually due to the paper deterioration. The digital collection is accessible online and goes from 1820 to 1969 (with a few hiccups). Yearly phone books are available at the City Archives building only, for the period after 1969.
Pick the type of almanac and keep clicking until you reach the beginning of the book you want to look at.
Click the magnifying glass at the top left of the page to clarify the image, then roll the mouse back to resize it so as to better fit your screen.
The search engine enable the searcher to retrieve articles by volume (tome), by year of publication, by author and by word contained in the article title.
Not everything that has been digitized is available online however and requires a trip to the City Archives building. Many unpublished manuscripts are also available by using the Pallas Catalogue, namely a large part of the registers of the Collection of historical Archives like the old cartuaries, the rules and jurisprudence of the city of Brussels from the Middle Ages until the end of the Old Regime.
To access the PALLAS catalog more easily, click "browse the archives" then open all the "+" signs in front of the different subjects. This will give you an idea of what is available and how to locate it - NOT online.
Archives de la Ville de Bruxelles
Rue des Tanneurs, 65
Tél. : 02 279 53 20
Fax : 02 279 53 29