Emmanuel Macron set up a damning photo that highlighted Rishi Sunak's absence from final D-Day events last week, Lord Cameron said today.
The Foreign Secretary said the French president called him over 'for a word' in Normandy before ordering the picture to be taken with the leaders of Germany and the US.
The image of the so-called 'quad' has since been used to batter Mr Sunak, after it emerged he left before the end to conduct an election campaign TV interview.
The premier has issued a grovelling apology and stressed he attended all the British events, but was again taken to task by the audience during a Sky News showdown last night.
Polls have suggested the story has cut through to voters, with Tories in despair that it could be a moment like Theresa May's meltdown over social care in 2017
Lord Cameron said the French president called him over 'for a word' in Normandy before ordering the picture to be taken with the leaders of Germany and the US
The image of the so-called 'quad' has since been used to batter Mr Sunak, after it emerged he left before the end to conduct an election campaign TV interview
In a round of interviews this morning, Lord Cameron did not deny he warned Mr Sunak against leaving the commemorations early.
However, he did dismiss the idea he was 'apoplectic' about the decision.
Asked on Sky News what conversations he had with the PM, Lord Cameron said: 'I'm not going to do that because I'm part of a team.'
He insisted: 'He had to make a decision, PMs have to make decisions all of the time.'
Describing how the photo of the 'quad' came about, Lord Cameron said: 'I was present at the American and French led event.
'President Macron asked to have a word with me. I went forward to have a chat with him, and he said let's have a quad photograph – that's Germany, France, Britain and America,' he said.
Asked whether any of the other leaders had commented on Mr Sunak's absence, the peer said: 'No.'
Lord Cameron told ITV's GMB: 'Prime ministers have to make lots of difficult decisions about when to go to things, and when to leave things, and who to see and all the rest of it.
'And to be fair to Rishi, he went to the key event in Portsmouth with all of the D-Day veterans in the UK, and then he went to the key event above the British Normandy beaches, that was again a beautiful event and he met lots of veterans there.
'Then he left to go back to the UK and then immediately said he had made a mistake and he had wished he had stayed, and I think we should should leave it there. Because that's the sort of guy he is, he made a mistake, instead of digging in and defending it, he said: 'actually, no, no, I got that one wrong I should've stayed'.'
Lord Cameron said it was 'time to move on to the substance' and pointed to the Government's track record of supporting veterans.
Mr Sunak has stressed that his itinerary for the D-Day events was set before the general election was called.
There have been claims from France that Mr Sunak intended to leave even earlier than he did, although No10 denied them.
In a round of interviews this morning, Lord Cameron did not deny he warned Mr Sunak against leaving the commemorations early. However, he did dismiss the idea he was 'apoplectic' about the decision
The premier repeatedly faced mocking laughter from the audience at the Sky News programme in Grimsby last night as he was grilled over the D-Day episode.
Mr Sunak reiterated his apology for his 'mistake' before saying: 'I was incredibly sad to have caused people hurt and upset, that was the last thing that I wanted to do. I hope people can find it in their hearts to forgive me.'
Mr Sunak - who is in Italy for the G7 today - said he has spoken to veterans about his party's work to help them.