So a greedy European state wanted their current/former colonies money.....
More to do with maintaining status quo than taking more
When the Libyan war hit /pol/ they correctly gauged that this was about Gaddafi's efforts to create a pan-African dollar, but they wrongly suspected the driving force was US fears of the US dollar being undermined, because nobody suspects the French and in hindsight the US dollar is so strong no one could really compete with it yet, Obama wouldn't authorize such an unnecessary war for the USA (probably)
For France that pan-african currency would be a different story
The CFA Franc is used by many West African and Central African countries that were former French colonies, or else had close ties with French colonies
The Franc offered stable currency that foreign investors wouldn't get their knickers in a twist about since it was backed by the French treasury, but it also meant that the individual African nations couldn't set their own interest rates or exchange rates, with effects similar to how the southern Europeans are being bent over backwards by Germany because they no longer control their own currency. With the Franc no longer being used in France itself the CFA Franc is now pegged to the Euro, effectively making West Africa fall under the European Union's hegemony. People call this neo-Imperialism, but if anything it is a rather classical one, before the Imperial powers annexed anything in the 20th century they first dominated economically in the 19th and all before that. A civil war in Libya would be a win-win scenario, as either Gaddafi's gold and oil reserves would be used up making a pan-African alternative currency unfeasible without a sizeable backing from Libya's treasury, or they'd win and Gaddafi's ambitions would die with Gaddafi
Plus this was during the period where all the former great powers were basically reevaluating their lives in the midst of America's decline from unrivaled freedom to a world where everyone's pushing everyone, same way as the Japanese and Chinese have exerted themselves in the Pacific, the Russians in Eastern Europe, the French in West Africa, the British around the Red Sea and central Asia, the Turks around the Aegean and Asia Minor, as well as all the new great powers rolling on and deciding they want in on this too, Iran, Saudi, Israel e.t.c. and the USA of course pretty much everywhere, I bring this up because I'm pretty certain this must've factored into Sarkozy's decision making process considering he involved France in the Arab spring, but mainly ones that had historical ties to France (Tunisia, Libya, Syria) as opposed to ones like Egypt or Iraq