I had planned it for a timeline in which Austria would have become the main European power in the 19th Century. Then Austria, not France, would have launched the 1830 Algiers expedition.
Even without this: in OTL, Austria had gained in 1815 a large access to the Mediterranean: Venice, Trieste, Ragusa... The POD comes in 1827, when the Dey of Algiers slaps the Austrian consul, and it happens that at that time Metternich wants to take the public opinion off more serious inner problems... Tunisia and Morocco will follow later, just as in OTL.
... Wait, you mean North Africa as it appears on a Risk map, including all OTL's Western and Equatorial French Africas? OK, this would need more and earlier adjustments