With the Ivory Coast and Mali drawing by the same scoreline earlier on Saturday, the opportunity to take the outright lead in the pool was on offer.
Volker Finke's Cameroon - who drew 1-1 with Mali in their opening match - struck first when Benjamin Moukandjo scored direct from a corner.
However, Guinea restored parity shortly before half-time courtesy of Ibrahima Traore's accurate drive.
Cameroon created the better openings in the second half with Vincent Aboubakar wasting the best chance when he put a free header wide inside the penalty area.
Each of Group D's four matches have now ended 1-1 despite stoppage-time drama that saw Stephane Mbia head wide when in a great position for Cameroon and Ibrahima Conte have strong penalty claims dismissed for Guinea.
Cameroon will now meet the Ivory Coast, while Guinea face off with Mali in order to determine who will reach the quarter-finals in the final round of pool matches.
Cameroon dominated the opening exchanges and only a fine save low to his right from Guinea goalkeeper Naby-Moussa Yattara kept out Aboubakar's side-footed volley.
Yattara endured a heart-in-mouth moment in the 11th minute when his attempted clearance struck Florentin Pogba and skewed just wide of the left-hand post.
Cameroon's pressure told from the resulting corner, though, as Yattara spilled Moukandjo's whipped near-post delivery into the roof of the net with the goalkeeper seemingly put off by a missed flick from Aurelien Chedjou.
After a slow start Guinea started to build momentum and only a fine defensive header from Raoul Loe prevented Fode Camara from pouncing at back post.
Joseph Ondoa then stood up well to deny Traore, who went one-on-one with the Cameroon goalkeeper.
But Traore would not be denied three minutes before the break as he turned sharply on the left-edge of the box and struck a sweet first-time shot low into the far corner.
Guinea's half ended on a sour note when Pogba was taken from the pitch on a stretcher with an apparent knee injury.
Traore almost scored a second in fortuitous circumstances shortly after the restart with a cross-shot that eluded Ondoa, but went wide of the far post.
Cameroon upped the tempo in search of a winner as Aboubakar tried an audacious 25-yard lob that went just over the crossbar.
The Porto striker was then guilty of missing a great chance when he glanced a header wide from Henri Bedimo's expert centre with Yattara in no man's land.
Cameroon continued to turn the screw and Aboubakar had a great chance to tee-up Moukandjo with 20 minutes remaining, but he could not adjust his feet and when the ball fell to Edgar Salli his shot was deflected for a corner.
There was then late drama as first Cameroon captain Mbia managed to head wide when unmarked in the box from point-blank distance, before Conte had legimate penalty claims waved away for Guinea when he appeared to be tugged to ground by Jerome Guihoata.
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