An investigation is underway in Paris after a second deadly fire in the space of a few days ripped through an apartment block housing African immigrants.At least seven people were killed, four of them children. The fire is believed have broken out in the stairwell of the rundown building near the French capital’s Marais district. Of the 14 people who were injured, three are said to be in a serious condition. Last Friday the Mayor of Paris Bertrand Delanoe was called to the scene of a fire which killed 17 African immigrants, many of them children. At the scene of this latest tragedy he said local officials were examining the circumstances of the incident including the state of the building and the families who lived there. It is not kown what caused the blaze – the third to have claimed the lives of immigrants in overcrowded buildings in Paris in four months. Authorities believe many thousands of people live illegally in such apartment blocks because of a shortage of housing in the city.