2. Is there a ban on donations from foreign interests to candidates?

Article 13, the resolution of the high independent instance of elections, 2022-17, 1 July 2022, the rules, procedures, and methods to financing electoral campaign: cash, in-kind, or advertising funds derived from:
-Foreign governments,
-Foreign legal entities, public or private, regardless of their activity, even if they have branches in Tunisia,
-Foreign natural persons, even if they reside in Tunisia or their source of income is Tunisian by tax legislation,
-Gifts, gifts, or grants whose source is considered foreign according to the tax legislation, regardless of the nationality of the funder.
-Financing Tunisians abroad for participants inside Tunisia,
Funding by Tunisians abroad for participants abroad is not considered foreign funding.

Article 80: it is prohibited to finance the campaign through foreign sources, including governments, individuals, or legal entities. Money that takes the form of a donation, gift, cash, in-kind, or advertising grant from a foreign source is considered foreign financing according to tax legislation, regardless of the nationality of the financier.
Funding by Tunisians abroad for candidates[40] for electoral districts abroad is not considered foreign funding.
The Authority sets financing rules, procedures, and methods that take into account the specificity of financing candidate lists for electoral districts abroad.

Article 163, organic-law 2014-16,2014, 26th May, of the elections and referendum amended by the decree 2022-55,2022, 15 September: 
Taking into account the provisions of Chapter 80 of this law, if it is proven to the Court of Accounts that the candidate, candidate list, or party has obtained funding from a foreign or unknown source for his electoral campaign, it shall rule obligating him to pay a financial fine ranging from ten to fifty times the amount of the value of the foreign or unknown funding source.
A candidate who enjoys foreign funding or whose source is unknown will lose his membership in the elected council, be punished with imprisonment for five years, and be obligatorily prohibited from running in any upcoming elections from the date of issuance of the conviction.

Unofficial English translation.

There is a ban on donations from foreign persons. It is an electoral infraction.