The Australian government has long been frustrated with the French contractor Naval Group over the latter's foot-dragging on the $90 billion submarine contract.

A Feb. 2021 article from ABC (Australian Broadcasting Corporation) goes into more detail on this deal:

According to this article from Bloomberg, this deal was made all the way back in 2016.

France had initially offered to sell Australia diesel-powered submarines that Australia did not want - either that or Australia wanted diesel-powered subs at first, only to have changed its mind later. France was running behind in supplying the nuclear-powered submarines Australia had requested, so the latter backed out of its agreement in favor of entering an alliance with the UK and US, angering France.

If I may offer my opinion on this, I believe the French are acting huffy over losing this lucrative arms deal, although I do question why the US had kept France in the dark about this new deal until almost the 11th hour. I do hope there was a good reason for that, and most of all, I hope that we can quickly smooth over these tensions.