I always try to release Occitania early if I can get into an opportunistic war against the French. It completely neuters their industry, forcing them to build up on their German border instead and making those provinces more attractive to Prussia. Nothing else fucks the French more long-term.
put a bunch of nihilists in charge of the intelligentsia and petite bourgeoisie, they are neutral on enacting the council republic (rural folk and trade unions were communists, landlords were weakened by a significantly huge industrialist group). as far as laws i passed laissez faire and commercial agriculture early and am keeping it under marx for the foreseeable future while passing a ton of social laws, capitalists are good at making peasants do more useful things also passed maxed out secret police and dedicated police force and bolstered trade unions. its important to find a good state and build all your industry in it and move your capital there to increase trade unions, im partial to bohemia and silesia. i moved my capital to bohemia after forming mega germany in 1846 (austria had a revolt, i supported them for an obligation, warred with the revolt leaders for german leadership, then dragged them into a war with france via the obligation. this resets their mood and then they will join you even as a great power)
funny enough council republic + laissez faire is probably the most stable law pairing in the game, it keeps industrialists and trade unions happy and you reap the happiness bonuses from both, which are both very good bonuses.
i also made marx go anarchist for multiculturalism, im not a fan of this, i wish vanguardism and communism also had multiculturalism. i think vanguardism is strictly better because it permanently keeps IGs in line and makes them all vanguardists so you can stack bonuses, but multiculturalism gives you a ton of benefits by receiving refugees from india and africa