Great to have you behind me on this one! Yes, most French Gardeners are Bio/and Lunar followers, in particular Bio-dynamic gardening uses the constellations and this is being introduced on the Radio and TV this year.
Anyway, back to the Moon's track across the sky and when you DON'T garden.
When the moon is at it's highest point and furthest away from the earth it is called 'apogee' - When it is at it's nearest point it is called 'perigee' - In both instances it is deemed harmful to plants and seedlings grow weakly and are prone to sickness. The primary cause is because if you imagine 'high and low tides' which we know are caused by the gravitational force of the moon/earth - At the highest and lowest position of the moon, it is effectively ineffective - neither pulling or pushing growth.
So these 2 points are known as 'noeuds lunaires' or knotted moons. ie. Fixed and doing nothing.Thus it makes sense to do nothing but basic maintenance on these days as indicated in the Calender.
Each Constellation favours Roots/leafy veg & herbs/Flowering veg/Seeds & fruits, and as the moon passes through the Constellations, strengths and weaknesses are denoted in growth
As the moon rises and passes through Capricorn & Taurus, and a descends through Virgo it covers Root Vegetables such as: Garlic/Beetroot/Carrots/Celeriac/Shallots/Turnips/Onions/Leeks/Potatoes & Radishes.
As the moon rises through Pisces and descends through Cancer & Scorpio it affects leafy vegetables such as: Asparagus/Cabbage/Spinach/Lettuce/Leeks/Chard/Rhubarb and aromatic herbs.
As the moon rises through Aquarius and descends through Libra & Gemini it has a favourable action on Flower-Vegetables such as: Artichokes/Broccoli & Caulifowers.
As the moon rises through Aries & Sagittarius and descends through Leo it favours the maturity of seeds and fruit such as: Aubergines/Cucumbers/Courgettes/Beans/Peas/Melons & Tomatoes.
This makes perfect sense to me as the higher it goes in simplistic wording - the more it pulls plants upwards, and the lower it goes it forces roots down. Following the course through the constellations would indicate it's strengths and weaknesses through each constellation on the relevant veg family.
Hope you are following this so far, because then you can begin to understand how the Calender works.
Calender to follow in next couple of hours - Plus some answers to questions (I hope!)