Complex sentence: In the 1980s, still the market leader in France and North Africa, the company acquired "Grands Travaux de l’Est", the starting point for expansion into countries surrounding the Indian Ocean as well as the diversification into its civil engineering activities.
Split into simpler sentences: In the 1980s the company was still the market leader in France and North Africa. It acquired "Grands Travaux de l’Est", which was the starting point for expansion into the countries of the Indian Ocean and of its civil engineering activities.