French Prime Minister Manuel Valls says the Rainbow Warrior bombing that took place 30 years ago was a huge mistake.
Mr Valls has made a fleeting trip to New Zealand - the first visit by a French prime minister for 25 years.
Mr Valls and New Zealand Prime Minister John Key held talks at Auckland Museum this morning and also had dinner together last night.
In July 1985, French spies detonated two mines attached to the side of the Greenpeace protest ship, Rainbow Warrior, as it sat in dock at Auckland's Marsden Wharf.
The ship sank within minutes, drowning Greenpeace photographer Fernando Pereira and sparking years of outrage at the French government's actions.
Mr Valls said the relationship between New Zealand and France had been patched up since those events.
"It's true that 30 years ago, our relationship was quite challenging ... that we had made a huge mistake, but I think that we have now turned over a new leaf, our relationship has changed."
Mr Valls said the two countries were now committed to looking forward, while remembering the past and never committing the same mistake again.
Mr Key said there was genuine acknowledgement from the French that the bombing was a terrible mistake.
"I'm sure they would never repeat that, they understand the pain and suffering that was undertaken by New Zealanders and the loss of life as a result of their actions.
"In the end actually the relationship has to be stronger than one thing, that was a big mistake by France, we have to look forward and put those things behind us, and I think the Prime Minister's visit here is just another way of continuing to build on the relationship."
He said France was an important member of the UN Security Council, as it was one of the five permanent members.
Mr Key said there was zero chance of France using its veto on Miss Clark's bid for the UN job.
"And for a pretty good chance actually, under the right circumstances, they would support her.
"They certainly knew the work she had done, they had respect for the roles that she had played and in France, Helen Clark could ultimately have a very good ally.
"But it's very early on and there are quite a number of candidates, and it is still possible for other people to come into the race, so people are going to play it quite close to their chest for a while."
Mr Valls said Miss Clark was very talented and had great experience.
"She's a very good candidate - obviously right now it is too early to have a formal opinion on the question, and we will be negotiating and discussing with each of the candidates."
Mr Key said he spoke to Miss Clark this morning and passed on the feedback from his French counterpart.