Following Italy in extending the lockdown but announcing no immediate easing of restrictive measures as in Spain, Macron said the tense situation in hospitals in Paris and eastern France meant there could be no let-up in the country.
Since March 17, France's 67 million people have been ordered to stay at home except to buy food, go to work, seek medical care or get some exercise on their own. The lockdown was originally scheduled to end on Tuesday.
"I fully understand the effort I'm asking from you," Macron told the nation in a televised address at the end of the lockdown's fourth week, adding the current rules were working.
"When will we be able to return to a normal life? I would love to be able to answer you. But to be frank, I have to humbly tell you we don't have definitive answers," he said.
Schools and shops would progressively reopen on May 11, Macron said. But restaurants, hotels, cafes and cinemas would have to remain shut longer, he added. International arrivals from non-European countries will remain prohibited until further notice.
Macron, whose government has faced criticism over a shortage of face masks and testing kits, said that by May 11, France would be able to test anyone presenting COVID-19 symptoms and give nonprofessional face masks to the public.
Macron also said he had asked his government to present this week new financial aid for families and students in need.
Acknowledging his country had not been sufficiently prepared early on to face the challenges posed by the outbreak of the new coronavirus, Macron appeared to seek a humble tone in contrast to the war-like rhetoric of his previous speeches.
"Were we prepared for this crisis? On the face of it, not enough. But we coped," he said. "This moment, let's be honest, has revealed cracks, shortages. Like every country in the world, we have lacked gloves, hand gel, we haven't been able to give out as many masks as we wanted to our health professionals."
The French, long accustomed to being told their high taxes paid for the "best healthcare in the world," have been dismayed by the rationing of critical drugs, face masks and equipment and have watched with envy the situation in neighboring Germany.
Macron's acknowledgment of the shortcomings was broadly well-received.
"It's not every day you hear a president offer a mea culpa and dare say 'we have no definitive answers.' Reassuring and necessary sincerity," analyst Maxime Sbaihi of the think tank GenerationLibre said.
After a relentless increase until the first week of April, the number of patients in French hospitals' intensive care units has started to decline, prompting health authorities to call a plateau in the epidemic.
But if French hospitals are just about coping, helped by a massive effort to transfer patients by plane, helicopter or even high-speed train from hospitals in the east and Paris to the west, nursing homes have been overwhelmed.
By Monday, the coronavirus had claimed 14,967 lives in France, the fourth-highest death toll in the world, with more than 98,076 confirmed cases, according to official figures.
"We'll have better days, and we'll return to happy days," Macron said.