Marine Le Pen has sought to modernise the FN in recent years and at her rally in Paris, she called herself the candidate of change, belief and action.
She launched a full-throttled attack on Mr Macron, calling him the candidate of "a morbid continuity, littered with the corpses of jobs transferred off-shore, the ruins of bust businesses, and the gaping holes of deficit and debt".
Ms Le Pen, 48, has capitalised on anti-EU feeling, and has promised a referendum on France's membership.
She has won support in rural and former industrial areas by promising to retake control of France's borders from the EU and slash immigration.
Mr Macron, the 39-year-old leader of the recently created En Marche! movement, earlier told the BBC that though he believed the European Union was still "extremely important for French people" it needed to change.
"We have to face the situation, to listen to our people, and to listen to the fact that they are extremely angry today, impatient and the dysfunction of the EU is no more sustainable.
"So I do consider that my mandate, the day after, will be at the same time to reform in depth the European Union and our European project."
Mr Macron added that if he were to allow the EU to continue to function as it was it would be a "betrayal".
"And I don't want to do so," he said. "Because the day after, we will have a Frexit or we will have [Ms Le Pen's] National Front (FN) again."