Why do Northern Africans give so much importance to French, while the lingua franca of this age was English?

I have been many times to the Maghreb and the point you are TOTALLY missing here it that is it MORE than they give importance to French they actually live in a stated of near total bilinguism French is NOT important there it is WIDESPREAD AND COMMONPLACE. They do recognized the importance of English and do use it in business. Spanish is also commonplace in many areas. Not everygone thinks like a bigoted anglo such as is the case in Canada where languages are only seen in a practical manner. You learn a language because you love the culture and what it stands for and in many cases that is English and the beautiful USA not because of its perceived practicality. The people of the Maghreb have no prob with this. To their great credit.

Couldn't you say many places that speak English were exploited and colonized by English speakers like Great Britain? Yet, they speak English. Many people speak French in West Africa and Europe, so there's nothing wrong with speaking French. It's still a major international language.

Because of French colonization and occupation. As for English, depending on the country you are in English is also taught in school and widely spoken. Tunisia has mandatory English classes. I agree with your added statement.

It was under occupation by france, not french territory. for stance Algeria was under occupation since 1830 till 1961