The hypothetical fact that the victim of the detained was not harmed does not relieve the petitioner from the requirement to demonstrate that he himself is harmed (argument of the text of Article 195, cited).

None needed.

HTH

"la cautelar" here means "medida cautelar", that is, some kind of injunctive relief.
The argument here seems to be the following (please check if it fits the whole context):
The "peticionario" has asked for an injunctive relief; the effects of such relief go on a third party's interests (the "víctima"; I think this word is misleading). The lawyer's argument is that, despite the "victim" suffers no harm, the original asker of the relief must prove that he or she is harmed (because the aim of the injunctive relief is to protect a right). So, if no right is violated, there is no need for any injunctive relief. Its (lack of) effects on the third party (the victim), are irrelevant to evaluate the need for such relief.
I hope it helps.

Best regards,

Patricia

that the subject of the preventive measure did not suffer any damages does not exempt the plaintiff from the obligation to demonstrate that he in his turn did (suffer damages). (Argument...)
I'm being very careful for the sake of the lawyer's argument.

I think Paul Stevens is right. Section 195 (Argentina's Civil and Commercial Procedural Code) reads:

"El escrito ¨[de las providencias cautelares] deberá expresar el DERECHO QUE SE PRETENDE ASEGURAR, la medida que se pide, la disposición de la ley en que se funde y el cumplimiento de los requisitos que corresponden [...]."

Patricia's reasoning is right, but I'd say "reasoning" instead. This section requests the petitioner to specify the rights he/ she is trying to protect. So it does not expressly request that the petitioner suffer damages, but such damages are IMPLICITELY required.

HIH!