There are many misconceptions about the differences between French corporate culture and Anglo-Saxon corporate culture, not least of which is the idea that there is any such thing as "Anglo-Saxon culture".
The one I want to address seems to be shared on both sides of both the big pond and the little sleave. That is the notion that French written communication is more formal than English.
It is commonly believed that the gulf between the way that the French speak and the way that they write is pretty big. Big enough to merit the word "gulf", at least. I have certainly encountered the peculiarity where certain words and figures of speech are considered normal when spoken aloud, but vulgar, or even offensive, when written down.
The French, in common with most Europeans, the British included, think that the Americans write pretty much the same as they speak. This is probably true in a few cases.
I think the error is in our understanding of the word "formal". Because "formal dress" normally means black tie or some other suitably sober attire, we tend to think that "formal language" is serious, stern, austere. But "formal" only means "having a particular form". By this measure, most soit disant Anglo-Saxon commercial prose is highly formal.
And the formality is no more valuable by being less serious.
While the predominant form in France - where formality occurs - is serious, formulaic and extremely pompous, the predominant form in the USA (and to a lesser extent the UK) is familiar, verbose, catchy and empty of meaning.
Of course, from my point of view, what the customer wants...
But what everybody needs is easy access to information in a way that is well adapted to his expectations and capacity.
So we should not allow ourselves to fall into a particular style when writing. We should choose a style that will suit the reader, then CHOOSE EVERY WORD.