The Royal Family and Prime Minister David Cameron were joined by around 400 British and Commonwealth veterans for a Royal British Legion service in Bayeux to honour the fallen.
During a ceremony at the Commonwealth cemetery, the Last Post was followed by an emotional minute's silence under sunshine and clear blue skies.
Yesterday's moving events included a fly-past of historic aircraft. Two Spitfires, a Dakota and a Lancaster bomber roared overhead in formation.
Earlier, a remembrance service took place in Bayeux Cathedral, with bible readings and hymns.
The Queen and Duke of Edinburgh were joined by the Prince of Wales and Duchess of Cornwall for the commemorations.
Deputy Prime Minister Nick Clegg, Scottish First Minister Alex Salmond and Labour leader Ed Miliband were among the congregation for the open-air service at the cemetery.
Foreign Secretary William Hague, Defence Secretary Phillip Hammond and Australian Prime Minister Tony Abbott were also there along with US President Barack Obama, Russia's Vladimir Putin, King Harald V of Norway, Czech Republic president Milos Zeman and German Chancellor Angela Merkel.
The Last Post was followed by a minute's silence. During a hymn, Charles and Camilla, Mr Cameron and clergy and dignitaries including Mr Salmond moved to a new bell created for the cathedral as a symbol of peace and freedom.
Charles named the bell Therese-Benedicte after Therese-Benedicte de la Croix, a German Jewish philosopher.
Born Edith Stein, she was arrested by the Nazis in August 1942 and sent to Auschwitz where she died. In 1999, Pope John Paul II canonised her.
Patrick Irwin, the Royal British Legion Chaplain to Normandy, told the congregation today was a reminder of the true cost of D-Day and the world was grateful for the veterans' courage and devotion.
Mr Cameron said he felt a mixture of "awe and gratitude" as he met veterans of the D-Day landings at the 70th anniversary commemorations.
The Tory leader said it was "incredibly moving" to be at the events in Normandy, and humbling for people of his generation who had not had to do anything like the heroic actions of June 6 1944.
He presented D-Day veteran George Batts, 88, with a special award for organising the pilgrimages to the landing sites for his comrades.
Grandfather-of-two Mr Batts, the national secretary of the Normandy Veterans' Association (NVA), was announced as the latest recipient of a Points of Light award for his voluntary work.
Mr Batts, who was honoured by a place with the leaders at the official state lunch after the service, was 18 when he waded ashore on Gold Beach with the Royal Engineers on June 6, 1944.
Mr Salmond added: "It is a tremendously moving experience to be here today standing alongside the bravest of men to whom we owe an incredible debt.
"It is important that we take time to recognise the sacrifices made here in Normandy 70 years ago by a generation who gave so much."
He described it as an honour to meet some of the Scots involved in the landings and added: "D-Day was a decisive moment in a war to maintain and preserve the democratic freedoms we are privileged to enjoy today, and the sacrifices paid by men from many nations made that possible."
Mr Obama paid tribute to his country's sacrifices at the Normandy American Cemetery and Memorial, where nearly 10,000 servicemen are buried.
He said the American commitment to liberty, "written in blood" on the beaches of Normandy, endures with a new generation.
The US president told D-Day veterans gathered above Omaha beach their legacy is in good hands.
French President Francois Hollande issued a rallying cry to the world calling on nations to act against threats to peace.
In a moving address delivered on the beach stormed by British troops on June 6, 1944, Mr Hollande said people needed the same courage as the Allied forces who fought and died to end Nazi tyranny.
He also called for the beaches of Normandy to become a UNESCO World Heritage site.
Mr Hollande said it was the world's duty to fight extremism and fundamentalism, adding: "It's up to us to have the same vision, the same courage, to be just as bright and have the same determination as those who came to these beaches 70 years ago."
The Allied assault on June 6, 1944 was the largest amphibious operation in history and marked the start of an 80-day campaign to liberate Normandy.
Three million troops were involved and 250,000 died, but the end of the war was brought closer as the Nazi hold over western Europe began to crumble.