Jordan's King Abdullah II and Queen Rania arrive at the Elysee Palace in Paris.
They're greeted by French President Francois Hollande, ahead of a massive unity march in the city.
Hardened rivals such as Israeli prime minister Benjamin Netanyahu and Palestinian president Mahmoud Abbas have also travelled here.
This week's three days of terror began on Wednesday when a pair of masked gunmen stormed the newsroom of the satirical newspaper Charlie Hebdo, killing 12 people.
Later a separate gunman killed a policewoman on the outskirts of Paris and four hostages at a kosher grocery store.