This fascinating, if not hugely cinematic, documentary takes care not to oversell its thesis. In the years leading up to the fall of apartheid in South Africa, a mysterious Franco-Algerian businessman negotiated a series of clandestine deals that accelerated the system's eventual implosion.

Many figures from the world of commerce (some still shrouded in obscurity) played analogous roles in the Northern Irish peace process, but the mechanisms at play in Plot for Peace seem even harder to summarise. Jean-Yves Ollivier is not exactly a social crusader. He had no time for economic sanctions and was happy to work with the perennially slippery Jacques Chirac.

We sense that negotiations were motivated as much by Olliver's desire to normalise business practises as by a need to set free the people of Africa. But, altered to the modern realpolitik during his days in post-revolutionary Algeria, he seems more attuned to the dynamics of coming convulsions than most politicians.

Plot for Peace tells a complex series of stories with great lucidity. The film is particularly good on the social backwardness of apartheid South Africa – a country stranded in the 1940s – and on the complex exchange of prisoners that took place in Mozambique in 1987. That last adventure abounds with twists and the sort of complex personal compromises that characterise the better John Le Carré books. As the film tells it, such operations constituted a series of dominoes that eventually led to the release of Nelson Mandela.

Sadly, the film does sometimes give in to broad strokes. The music pounds more often than is desirable. The shots of Ollivier playing long games of patience will strain the patience of even the most tolerant metaphor enthusiast.

This remains, however, a gripping exploration of a geopolitical sideshow that deserves greater exposure. The simple explanations are so often the wrong ones.