What event forced Louis XVI to sign the Declaration of Rights of Man?

The Declaration was endorsed by the National Constituent Assembly and delivered to Louis XVI for endorsement. As Eric Hobsbawm puts it, the king "resisted with his usual stupidity" and refused to sign. He refused his assent until October 5th, when he signed the Declaration to placate angry crowds at Versailles.

he signed the Declaration to placate angry crowds at Versailles.