I would say that the dog poo issue has really improved with the years, it is still a problem but far less than before.
Fare jumpers are a problem in France, they estimate at around 7-10% the number of people who fraud on the public transportation. You can even find some associations where people share information on how to defraud the system and self-insure themselves against the fines. They see this as a way of protesting the fact one should pay for public transportation. Then you have the cost of the controls that sometimes is higher than the fraud and the fact that enforcing the payment of fines is very difficult in France.