Where to find the code
Somewhere on every Champagne label, there will be some writing in tiny font. That's where you're going to find the two letter code. On Godin et Filles bottles, it's at the very bottom of the rear label where you'll see the code "RC". Others may have it somewhere on the front label.
What the codes mean
Let's start with our favourites, the codes that tell you the people selling the Champagne are the people who grow the grapes.
RM & RC. These codes stand for Récoltant Manipulant and Récoltant Cooperateur. Récoltant translates to harvester, so the R is a nod to the connection of these producers to their vineyards. The essential difference between these codes is that RM is for those making the Champagne with their own winemaking facilities, whereas RC uses the facilities of a cooperative of growers. Godin et Filles are Récoltant Cooperateurs as they use the facilities at the Cooperative in their home-town of Berru. Their production is currently too small for dedicated winemaking facilities to make financial sense, but this way they still maintain full control over style and quality.
These Champagnes tend to be available in much smaller volumes (sometimes just a few thousand bottles in total for the producer) because they are limited to their own vineyards. In Australia, you can expect these to generally be of high quality because, well, why would anyone commit to importing and marketing a Champagne that will be relatively expensive compared to the mass-produced bottles, unless it was something special?
CM: Coopérative Manipulants are grower cooperatives who pool their harvest and sell Champagne under a joint label. They range in size with the biggest and best known being Champagne Nicolas Feuillatte whose growers cover roughly 9% of vineyards in Champagne and produce over 20 million bottles per year.
NM: Negociant Manipulants, also known as Champagne Houses, buy grapes from growers (often in addition to grapes from their own vineyards) to sell under their own brand. This enables them to dramatically increase the volume of Champagne they can sell and includes the biggest global Champagne brands like Moët & Chandon and Veuve Clicquot who sell 20-30 million bottles per year. Up until the current generation, the Godin family had sold their harvest to these Houses. We're so happy they've recognised that their grapes deserve better!
MA: Finally, we get to the homebrand category. Marque d'Acheteur means "buyer's brand". The producer will make the wine already labelled with the buyer's brand, which the buyer then markets. Mostly these are for supermarkets, but sometimes there may be small productions specifically for a restaurant, for example. They'll be very competitively priced... sometimes you can pick them up for under $40 but you get what you pay for. See if you can find the Dan Murphy's homebrand on their shelves next time you visit :)
There are a few other two letter codes allowed under the regulations, but the codes above cover the main ones you are likely to come across in Australia. Go support a récoltant today!