I preface this with the fact i got this first attempt, so may have been dumb luck (germany did some stupid stuff)
Strategy:
Troops - bring all colonial troops home, and convert them all to your std infantry template
Create 1 production line of mountaineers - indefinite repeat
Create 3 production lines of infantry - in definite repeat
Other than this focus all resources on teching up existing troops and replenishing materials used having your troops run exercises (you need this to ensure your troops are all regular when fighting starts, and give you exp to add 2 Arty, 1 AA + support field hospital, engineers, arty and recon to both your mountaineers and inf templates)
With the navy i disbanded all ships that were lvl 1 except the carrier and BBs - every bit of manpower helps.
I ignored airforce completely
24 divisions manned the traditional maginot line, all other infantry on the belgian border, all the mountain troops on the italian border.
Industry wise - for the first few years 1936/37 made roughly half and half civ and mil factories, after that got lvl7 forts along the belgian and italian borders (belgian first, as normally germany will hit you before italy joins the axis), once had those up went back to beefing up industry, still roughly half and half.
Tech research:
focused on industrial, infantry, artillery, AA, land doctrine in roughly that order. Switched the doctrine from the trench warfare one to the american one for the arty bonuses (note this research will take forever while you have the great war modifier)
National focus:
Did the mainland France ones down to the extra research slot first, then the defensive one that gives you discounted weygand, then the political ones down to where you side with Britain, then back to the military ones, prioritising the fortification focuses.
When war breaks out, chill out behind your massive fences and wait for the axis to run out of troops. enjoy.