In an evenly-matched encounter, Pierre Webo spurned the best chance to win the game for the visitors in the second half, meaning that the Indomitable Lions will approach the return fixture in Yaounde on November 17 on an even basis.
After speculation surrounding Samuel Eto'o's international future, the forward was named in Cameroon's starting XI by Volker Finke, but the Chelsea man rarely threatened.
The hosts began brightly as Yassine Chikhaoui forced Charles Itandje into a smart stop with a fierce drive from inside the area in the opening minute.
Houcine Ragued and Saber Khalifa both saw headers saved by Itandje shortly after Chikhaoui's early opportunity as Tunisia continued to apply the pressure.
After Eto'o saw a tame attempt easily saved by Moez Ben Cherifia, Wissem Ben Yahia's dipping effort had Itandje scrambling once more to keep the scores level.
Jean Makoun almost put the visitors ahead four minutes from the break, but put his effort the wrong side of Ben Cherifia's left-hand post.
Cameroon, seeking to book a place in their seventh World Cup finals, also struggled to assert themselves after the break, with Ben Youssef heading a Sameh Derbaly cross just wide after 55 minutes.
But Webo then missed the best chance of the game as he failed to convert an Allan Nyom delivery in front of an open goal with 22 minutes remaining.
And though the game became more open in the latter stages, neither side could strike late on, as the tie remains finely poised ahead of the second leg.