Per the Red Michelin Guide
3 stars means the restaurant merits a special trip. The food, wine, decor and service will be exceptional and you should expect to pay and you should probably leave the kids at home.2 stars indicates the restaurant deserves a detour. Everything will be top-notch, if not perfect, and you should not expect a bargain.
1 star means that if its on your way, you should stop. For the kind of restaurant it is, a one star establishment should serve very good food in a pleasant environment. But, the Guide warns readers not to compare the very-fancy "de luxe" restaurant that has one star to a simpler restaurant "where you can appreciate fine food at a reasonable price."
