Great link, thanks. However, it doesn't back up the claim you made. A few quotes:
"In Europe, there is technically no uniform body of “European law” that directly applies between employers and employees"
"Courts and scholars increasingly reference EU law, usually without clarifying whether the existence of a particular civil right protection in the EU Charter actually changed the legal situation as a matter of law, rather than as a matter of public policy."
There's a lot of fuzziness around implementation of a very loosely worded human rights clause, combined with prior national laws. Mostly aimed at protection from Government. Previous tests have mostly been cases where the individual did not consent or some such thing.
More directly, EC data protection directive hinges on: 1) contractual obligation; 2) consent; 3) statutory obligations; 4) balancing test. It seems highly likely that most business can legally MITM me if I sign the contract they want me to sign.
Most - but not all - of the private sector examples given (including Germany and France) hinge on the employer not following the correct process: either not notifying the employees, not gaining consent, or opting to allow private communications at work which are strictly forbidden from being monitored (in some countries).
That said, there is also:
"A number of EC member states, including Germany, Italy, the Netherlands, Spain, and the United Kingdom, strictly prohibit ongoing monitoring of employee communications and permit electronic monitoring only in very limited circumstances (e.g., where an employer already has concrete suspicions of wrong-doing against particular employees),265 subject to significant restrictions with respect to the duration, mode, and subjects of the monitoring activities"
It's not immediately clear if the applies to specific, targeted monitoring. The footnote says gives an example where informing the employee of valid reasons for investigating is sufficient.