It is legitimate for the employer to monitor its employees in the correct fulfillment of their duties, directly or through the managers that report to him and are known to the employees.

Court of Cassation, Employment Section, Judgment of 9 October 2020, no. 21888

It is indeed legitimate for an entrepreneur to monitor his employees in the correct fulfillment of their duties, directly or through the managers that report to him and are known to the employees, In order to ascertain any specific failings, already committed or in progress.
In the case in question, a mailman had been dismissed for disciplinary reasons due to lack of diligence and for a persistent failure in carrying out his duties. 
Both the Judge in first instance and the Court of Appeal threw out the claim of unfair dismissal, finding that the facts complained of showed a stubborn delay in the performance of his duties and carrying out instructions, manifested through the patchwork delivery of correspondence without any plausible justification. 
The Judges on the merits held as unfounded the allegation that there had been a breach of the duty of supervision (Article 3, Law no. 300/1970) as this provision undisputedly referred to monitoring entrusted to external personnel.
The worker appealed to the Supreme Court of Cassation, claiming that the Court of Merit had erroneously excluded the breach of law in the case of checks carried out by employees of the employer, regarding compliance of the worker’s contractual obligation to do his job, as such checks should be limited to illegal acts, not just non-compliance.

The Supreme Court of Cassation rejected the appeal.
The Supreme Court of Cassation clarifies that «the case in question is governed by Article 3 of Law No. 300/1970 (“the names and specific duties of the staff responsible for supervising the work must be communicated to the workers concerned”) and not by Article 4 of the same law that regulates, however, the matter of controls through the use of audiovisual equipment and other equipment (Cass. No. 7933 of 1998; Cass. No. 1263 of 1982)».
In the case in question, the worker’s activity was, in fact, monitored by «the managerial hierarchy of the company (the worker’s superior and member of the Inspection Office)».
As a result, the Supreme Court of Cassation, upholding the judgment on the merits, reiterates that «the provision of Article 3 of Law no. 300/1970 – according to which the names and specific duties of the staff responsible for supervising the work must be communicated to the workers concerned – did not affect the power of the entrepreneur to control directly, or through the the managers that report to him and are known to the employees, the worker’s performance and therefore, to ascertain any specific failures of the employees themselves, already committed or in progress: this independently from the way in which the checks have been carried out, which can legitimately take place also covertly, without the principle of correctness and good faith being breached, above all when such methods are justified, given  the previous misconduct of the employees (Cass. n. 829 of 1992; Cass. n. 7889 of 1996; Cass. n. 3039 of 2002)».