Complex sentence: Marie-Hélène Lefaucheux (26 February 1904--25 February 1964) was a women's and human rights activist and member of the French delegation to the United Nations.
Split into simpler sentences: Marie-Hélène Lefaucheux (26 February 1904--25 February 1964) was a French women's and human rights activist. She later became a member of the French delegation to the United Nations.