Mr Macron comprehensively defeated far-right candidate Marine Le Pen and will become France’s youngest president, as well as the first from outside the two traditional main parties since 1958.
“I am delighted Emmanuel Macron and centrist, progressive politics has prevailed against far-right populism and fascism,” said Mrs Long.
“Politics around the world needs more moderate representatives, with policies based on what unites people rather than divides them. We need to tackle fascism in all its forms.
“I hope the example of France travels elsewhere and inspires voters to back other liberal, progressive parties across the globe, including in the forthcoming General Election here.”