As the largest francophone country in sub-Saharan Africa - and the second-largest French-speaking country in the world, Zaire was of great strategic interest to France. During the First Republic era, France tended to side with the conservative and federalist forces, as opposed to unitarists such as Lumumba. Shortly after the Katangan secession was successfully crushed, Zaire (then called the Republic of the Congo), signed a treaty of technical and cultural cooperation with France. During the presidency of de Gaulle, relations with the two countries gradually grew stronger and closer. In 1971 then-Finance Minister Valéry Giscard d'Estaing visited Zaire. Later, after becoming President, he would develop a close personal relationship with President Mobutu and became one of the regime's closest foreign allies. During the Shaba invasions, France sided firmly with Mobutu: during the first Shaba invasion, France airlifted 1,500 Moroccan paratroopers to Zaire, and the rebels were repulsed. One year later, during the second Shaba invasion, France itself would send troops to aid Mobutu (along with Belgium).