21 minutes ago, geordief said:

start preheating the oven to 300°C

That rules out my oven. Is 300 correct?

30 minutes ago, mistermack said:

That rules out my oven. Is 300 correct?

I have never made baguettes but that temperature is similar to what you would use in a pizza oven -a bit less.

I guess it must be right 

Not sure what the water is for(to stop the bread going on fire?)

52 minutes ago, geordief said:

1. Put the water to cool in the microwave (about 35 ° C)

Hi.  Have no major problem reading french, but problem with the above.  😃

Sent an email to a yeast manufacturer; hope to get more knowledge.  Found something else half way down this page ---> https://www.fleischmannsyeast.com/frequently-asked-questions/

15 hours ago, Externet said:

What prevents the yeast from meeting death in sub-freezing temperatures ?

Being small.

On a related note...
https://www.snopes.com/fact-check/the-biscuit-bullet/
I thought everyone knew you could get frozen dough.

1 hour ago, geordief said:

I have never made baguettes but that temperature is similar to what you would use in a pizza oven -a bit less.

I guess it must be right 

Not sure what the water is for(to stop the bread going on fire?)

At 300C a pizza would fully cook (and subsequent burn) within 3-4 minutes, usually. So baking them in that temp for 20 mins  seems a bit off. I suspect that there is some mistranslation going on, as the recipe also calls for yeast despite being yeast-free (microwaving water to lukewarm is typically also for activating yeast, so double-weird).

Water (or rather steam) is often used to create the characteristic crust on baguettes (or what you can find in buns in Europe) as well as help with the rise in the early phase of baking. Commercial bread ovens (in Germany at least) typically have a steam function for that purpose. 

Not sure if already mentioned, but for bread you would generally want "strong" flour (i.e. protein content of >10%).

Also as John already noted, freeze-thaw cycles damages cells, but not quantitatively (i.e. only a proportion at any given time). 

Seems a recipe from a lazy 'copy and paste' illiterate.    "1 sachet de levure chimique" also tells nothing, no measure unit. 🥴