Van Basten put forward a number of suggestions this week, including scrapping the off-side rule, limiting the number of fouls one player can make during games, and a sin-bin.
The Dutch legend also put forward the idea of replacing penalty shootouts with eight-second run-ups in a one-on-one situation with the goalkeeper, amongst others.
Gourcuff, along with a number of Premier League managers, feels the changes would only make for a poorer game.
Ahead of his side's Ligue 1 match with Guingamp, he said: "This is the worst c**p I have read in a long time and yet I did not read it wrong.
"It's immeasurable bulls**t.
"We would return to the time of village versus village, and at the time it ended with players being killed.
"The offside is a manifestation of collective intelligence. There would be no more collective spirit if the offside rule was removed.
"The offside rule is fundamental - if you do not understand that, you do not understand football."
Meanwhile, Arsenal manager Arsene Wenger is also in support of keeping the offside rule. He said: "Some of the proposals are discussable, some of them I don't see any big interest in.
"The one I don't find interesting is to suppress offside. I think offside is what makes the teams fit together, it's a big quality of the team sport, an intelligent rule. It's very important to keep that in the game."
Tottenham manager Mauricio Pochettino also had his say. "I understand that sometimes when you are in a position you need to try to find ideas, but I don't want a system without offside.
"If we play without rules, we have to be careful with that. I read some sentences but I don't know.
"My first impression I think is, be careful. Because in football to change the rules is a very difficult thing."