Yes , you are probably right when it comes to language as a issue, but consider these following factors
1. You can apply across Europe if you take RSM
2. 18 months of stay back in Europe, compared to 1 year in Singapore
(Not sure if this is a factor, essec is basically based in Paris. Are the branches equal in overall merit and rank ?)
If you do get a chance to do your mim in France, think over it...as learning a new language isn't as tough as you might think