Posthumous marriage in France is legal but must be approved by several civil servants and the family of the deceased. France is one of the few countries in which it is legal to marry a partner posthumously.

A few women were married by use of proxy to soldiers that had died weeks earlier. This practice came to be called posthumous marriage. Posthumous marriage for civilians originated in the 1950s, when a dam broke and killed 400 people in Fréjus, France, including a man named André Capra, who was engaged to Irène Jodart. Jodart pleaded with French President Charles de Gaulle to let her go along with her marriage plans even though her fiancé had died. She had support from the media and within months was allowed to marry her fiancé. It is likely that posthumous marriage (un mariage posthume) was made as an extension to France's proxy marriage.

Within months after the Fréjus dam tragedy, France's parliament drafted a law permitting posthumous marriage. Since then, hundreds of women have formally filed for what is known as postmortem matrimony.

More Info: en.wikipedia.org