To obtain a student visa, one should get an offer letter from the French University of his/her choice. Then only they can obtain for a student visa. Moreover, the student has to get the Visa before he/she leaves their resident country.
French Government is not eager to provide jobs, due to high unemployment. In addition, France is infamous for its extensive red tape, which can make everything from buying a car to renting an apartment an administrative nightmare.
One common job for students is an au pair position.
Marry a French citizen will facilitate to obtain French citizenship to some extent. But a lot of paperwork is also required. In other words, marriage will not automatically make you a French citizen.
Though, there are ways to find the work that pays you under the table, they are highly risky as they are illegal.
List of required documents: