145-year-old Paris letter discovered

A letter from a man to his mother flown out of Paris by hot air balloon during the Prussian siege in 1870 has turned up in Australia's National Archives, which said on Tuesday it was keen to discover the family's fate.

The Franco-Prussian War saw the Germans completely surround Paris for more than four months that year.

Balloon mail was the only way communications from Paris could reach the rest of France, with dozens of flights made, mostly at night, and hundreds of thousands of letters delivered.