All four goals came in an entertaining second-half as Cameroon, coached by German Volker Finke, came within a whisker of a historic first win over Germany.
The Africans took a shock lead through Chelsea's Samuel Eto'o on 62 minutes only for Germany to equalize four minutes later through Thomas Müller.
German replacement Andre Schürrle gave the hosts the lead before Cameroon left-wing Eric Choupo-Moting, who plies his trade in the Bundesliga for Mainz 05, popped up with the 78th-minute equalizer.
Cameroon avoided their second consecutive defeat after losing 2-1 to Paraguay last Thursday, while Germany were missing stars Philipp Lahm, Manuel Neuer and Bastian Schweinsteiger.
Germany host Armenia in Mainz on Friday in their final match before flying to Brazil on Saturday as they face Portugal on June 16th in Group G.
Real Madrid's Sami Khedira looked sharp for Germany, despite spending most of the last six months on the sidelines, while Cameroon captain Eto'o was a constant threat.
With both Germany's captain Lahm (ankle) and goalkeeper Neuer (shoulder) out with knocks, Arsenal centre-back Per Mertesacker skippered the side.
Roman Weidenfeller deputized for Neuer in the German goal, while vice-captain Schweinsteiger sat out the friendly with tendinitis in a knee ligament.
Germany coach Joachim Löw opted to start with Bayern Munich's attacking midfielder Mario Götze up front in the 'False Nine' position.
The hosts made a bright start with Mesut Ozil firing wide in the first minute, Mertesacker heading over and Götze hitting the post with barely ten minutes gone.
Cameroon's first chance came when Eto'o held off Khedira to fire a low-shot which Weidenfeller stopped on 18 minutes.
The Africans started putting in some loose challenges as Eyong Enoh was shown a yellow card on 20 minutes for bring down Manchester United-target Toni Kroos.
Barcelona's Alex Song joined him in the referees book soon after for tackling Khedira from behind.
Cameroon's Benjamin Moukandjo squandered the best chance of the first half by firing straight at Weidenfeller after Eto'o superb defence-splitting pass with half-time approaching.
Cameroon took the lead with an hour gone after punishing some sloppy German defending.
Weidenfeller parried Eto'o's shot, but Choupo-Moting pounced on the loose ball and fired in a cross from the left flank which the Chelsea striker fired home.
The lead lasted just four minutes as the hosts pulled level when Boateng managed to drag the ball back for Müller to hit the net.
Germany pulled ahead when Arsenal's Lukas Podolski produced a powerful run and squared the ball for Chelsea's Schürrle to tap home on 71 minutes.
But the Africans roared back when Choupo-Moting drove his fierce shot past Weidenfeller 12 minutes before the final whistle.
Enoh could have grabbed a late winner for Cameroon, but his shot from 20 metres out just passed over the crossbar to spare Germany's blushes.