What is the ruling on conducting a civil contract several months before marriage, given that the Shar'i contract is not permissible in Tunisia according to some Salafi sheikhs as a pre-emptive measure, and due to the family's refusal of this?

There is no doubt about the seriousness of marrying without documenting the contract. If the civil contract fulfills the conditions and pillars of marriage, then obedience to parents in rejecting it is not obligatory when there is a need for marriage. However, if it lacks some conditions, such as requiring a guardian (wali) or witnesses, then it is invalid according to the majority of scholars.