Do you feel that the author is being critical of the values of the society of his time in a subtle way? Would this criticism hold true in this age also?

That's an interesting question. Madame Loisel, to be sure, seems to have all her priorities in the wrong order. She has a husband who loves her, and he has a secure (if minor) position in the government. Then, when her husband pulls some strings, going to a significant amount of trouble to procure the pair of them an invitation to a big fete at the home of the Minister of Education, she is completely ungrateful. She needs a dress, she says, so he gives her the money for a dress—money he'd been saving to buy himself something. Then she is not happy with the dress unless she has some jewels.
Maupassant certainly criticizes anyone of a similar mind to this materialistic and ungrateful woman. But her husband is not like her, so it does not seem as though her misguided ideas about what is most important in life are shared by everyone (or anyone else in the story). So, I'm not sure this reads as social criticism so much as a more specific kind of criticism that targets people like Madame Loisel, and because this type of person exists in all ages, it stands to reason that Maupassant's criticism would apply to our current era as well.