Robert le Maçon, Sieur de la Fontaine, or Robert Masson, (1534/5–1611) was a French Reformed minister and diplomat. He founded an important church in Orléans which became central to the Huguenot movement during the first French War of Religion 1562. Fontaine became minister of the French church in London. In 1586 Francis Walsingham wrote to him, asking him to establish a French church in Scotland. His three daughters married members of the Harderet family, Huguenot merchants and goldsmiths in London.