Paul Almasy took this photograph of nuns working at a hospice in Paris in 1952. The photographer, a Hungarian aristocrat who had given up a career as a diplomat to become a journalist, had based himself in the city after the war. Most often in this period – as a new book of his work, Paris, reveals – his camera dwelt on the lightness of the city as it reinvented itself: lovers dancing by the Seine, little visions of serendipitous comedy or grace in bars and cafes. The formal geometries of this photograph – which captures the Filles de la Charité of the order of St Vincent de Paul – is unusual in this work.

Social distancing was, and is, a way of life for the nuns, popularly known as the “grey sisters”, who were required to take four annual vows of poverty, chastity and obedience in the service of the poor. The absence of shadow from the figures suggests that Almasy found his vantage to look into the courtyard at around noon, when the nuns were required to meditate and examine their consciences. The singular dress of the order, the white linen head-dress or cornette – prototype PPE – was established at the time of their foundation in the 17th century.

In some ways, this photograph gave an indication of the future direction of Almasy’s work. Later that year, he became an official photographer for the United Nations, working in particular for the World Health Organization, for which over the following decades he produced hundreds of stories, capturing the success and failure of fighting disease across the globe. By the time of his death in 2003, aged 97, he had gathered an archive of 120,000 pictures, always using a diplomat’s discretion: “When I took photographs I never crouched down like a cat about to pounce on its prey,” he said. “I never attacked with my camera.”

Paris by Paul Almasy is published in May (teNeues, £12.50)