It is absolutely true. Forced labour was used in every single colonial empire in various different forms.

One was the use of forced labour of prisoners of war. So a polity would lose a war and it's people would be put to work as unpaid labourers. A very good example of this would be the Herero Genocide in German South West Africa.

The initial genocide was the declaration by Lother von Trotha that every member of the Herero would be killed. This was eventually, after several days delay, revoked by Wilhelm II at the request of his ministers.

The remaining Herero were put to work on building railways instead, as were the Nama when they were captured later. This is slave labour, the death rate of the workers was appalling, up to 70% on certain tracks, rapes and other abuse were common place and no wages were paid. It was justified by being restitution for the damage caused during the war. This pattern of war prisoners and criminals being used for free labour wasn't uncommon.

Then you have corvee labour. As in labour being taken instead of taxes. This was very common in French colonies, French Madagascar often demanded labour instead of taxes from the people who had been serfs in the Merina Kingdom. In the book Vichy in the Tropics, there's some detail as to how this was a massive part of Vichy French rule of Madagascar in WW2. And a lot of companies had control of areas of French Equatorial Africa and would take labour from villages in their area.

As an example Jean-Bédel Bokassa, who would later become the First Emperor of the Central African Empire, grew up in the Lobaye basin wherein the French Forestière company held sway. This company would impress whole villages for forced labour and take hostages to ensure the workers would obey. When Bokassa’s father tried to free these hostages, he was beaten to death in the village square as an example to the others.

This was more infamously also the way labour was obtained in the Belgian Congo. Wherein the army would march into a village, hold the woman hostage and force the men to collect rubber for them (by climbing the tree, slashing the rubber vine open with a knife then staying there for days while the rubber dripped out of the vine and onto their body where it dried. And then it had to be painfully ripped off the worker's body, often taking hair and skin with it.) or they'd kill them all. The Congo Free State, when it was personally owned by by the King of Belgium, was widely condemned at the time for being a slave state. 'Volunteers' for the army were literally bought into Belgian towns in chains and then conscripted. Workers were not paid and were routinely whipped and killed. And thousands were worked to death with no chances of quitting.

After the Congo Free State was bought by the Belgian government and the atrocities were reduced, the system of forced labour continue. Up until the 1920s taxes could still only be paid by labour in large areas of the Congo.. And conscription into the mines, still happened. The British industrialist William Hesketh Lever, the 1st Viscount Leverhulme, set up various palm oil factories in Belgian Congo in the 1920s and mostly that was staffed by unpaid workers. There's a great book about this in particular called Lord Leverhulme's Ghosts.

This also happened in Portuguese colonies, such as the rubber farming in Northern Angola. But the Portuguese in those areas also bought slaves from independent or semi independent Kingdoms. The Portuguese in Africa were notorious slave traders. This was also relatively common in later 19th century and early 20th century Africa in places like the German Cameroon. The colonial powers would install a protectorate over a kingdom and take tribute in terms of labour which the kings would provide, and this would be slaves. So the Kingdom of Dahomey in Benin during the 1890s prior to it's conquest in 1894 often made trade deals with the Germans and Portuguese which involved exchanging goods for labour and that labour was slaves.

In British Africa you also had labour imported from India. These workers were normally paid but they were locked into five year contracts which they had no hope of breaking and often didn’t know what they were signing when they’d joined up.