In france, there is no general obligation of fairness in hiring. Only a specific list of criteria constitute illegal discrimination, such as physical appearance, gender, religion, political opinion or activity, etc. This also includes indirect discrimination: discrimination on other criteria that are not directly relevant on their own, and are strongly correlated with illegal criteria. Any such discrimination must be based on a legitimate objective and must be a proportionate constraint to reach this objective; for example, gender-based discrimination is legal in a very small number of professions (actor, mannequin, model); age-based discriminations can be based on safety considerations; refusing to hire a handicapped person because they have been declared medically inapt for a job is legal...
An additional consideration that indirectly limits to hiring discrimination is that an employer may only ask candidates about information that is relevant to the candidate's capacity for the job. So some discrimination may be, in principle, legally impossible because the employer could not know. However, if the employer does find out anyway, discrimination on criteria that are irrelevant but not expressly illegal is legal.
Exclude internal applicants from consideration for jobs for which they have relevant qualifications
It is legal to favor internal candidates for a job, and it is legal to advertise a job without looking for internal candidates. (There is one case that may seem like an exception exception, which is that a company who wants to lay off workers because their current position is made redundant generally must offer them another position if possible. Thus, in this case, internal candidates do have precedence over external hiring. However, what would be illegal if the internal candidate is not given precedence is not the hiring, but the layoff.)
Once hired, conditions are stricter: salarial differences must have some objective basis, the contours of which are defined by complex jurisprudence. In principle, taking a candidate's salary negotiation into account in order to decide whether to hire or not is legal, but paying different hires a different salary based on their negotiation skill is not. Taking qualifications such as degrees into account is legal, even if the qualification is not an absolute requirement for the job, as long as it has some form of relevance.
Summarily hire members of the business owner's family
This is legal, since the law doesn't say otherwise. Discrimination based on marital status or family name is illegal, but choosing to hire a particular person based on their membership in a specific family isn't.
Exclude close family/marital relations of existing employees
Systematically rejecting spouses (or unmarried partners) of existing employees may be illegal due to the fact that discriminating based on marital status is illegal. I don't know what the jurisprudence is. If the employer needs to ask, this likely falls under the proscribed questions.
Hire non-local (here defined as those who can commute to work from their existing home) candidates in preference to local ones similarly qualified
Specifically hiring non-local candidates in preference to local ones is illegal. But so is specifically hiring local candidates in preference to non-local ones. The place of residence is an illegal discrimination criterion.
Hire foreigners where they have suitable work permits
Again, specifically hiring foreigners would be just as legal, or just as illegal, as specifically refusing to hire foreigners. In addition to the place of residence, the origin is an illegal discrimination criterion.
This is specifically about discrimination based on nationality, where the candidate is already authorized to work in France. If the candidate needs to obtain a work permit, this work permit needs to be authorized, and in many cases, this will require an assessment that no EU/EEA national could be found.
All of this is about hiring in the private sector. The civil service has its own, much stricter rules. The general rule in the civil service is that recruitment is by competitive examination.