Back in February 2006, I answered a question on a website about the short French phrase "à proprement parler". However, in this text, it had been spelled "proprement parlé", and that was the question that was actually asked.

Having established that the conventional phrase was indeed what the text should have said, in this particular case, although typically "strictly speaking" or something along those lines would work, I suggested a work-round which avoided having to specifically translate those three words at all. To paraphrase what I said, the author was using it to avoid confusion between two uses of one phrase (poste de travail) in French - if you use two different English terms, Bob's your uncle.
No need to worry about working "strictly speaking" into the sentence at all! The asker of the question accepted this solution.

And the years rolled by and I forgot all about it....

...until April 8, 2009, when I was a bit surprised to get an email, notifying me of disagreement. People are allowed to disagree, of course. But this was a disagreement that added nothing to a discussion that ended over 3 years ago, proposed a solution that was patently wrong, and was effectively anonymous, as the person had adopted the username of "Classified Classified"* (the person has a profile which is borderline obsessive about maintaining privacy). The comment said:

proprement parlé = "in plain (simple) language".....

I clicked through to the link, since the website allows one to comment on comments, and decided to encapsulate my annoyance at the pointlessness of the contribution thus:

"It's certainly an interesting opinion, but we can all be "interesting" when we are posting anonymously. I think you are very, very wrong in this case, but I would not say it can never be translated as you describe."
I thought that represented a reasonable response, under the circumstances - namely my inability to think of a single situation where "in plain language" might actually work

Perhaps I should not have been surprised to receive the following charming missive not a day later (it starts by quoting me to me, as an alternative to "Hi" or "Hello" or "Dear Charlie" or anything pleasant):

"It's certainly an interesting opinion, but we can all be "interesting" when we are posting anonymously. I think you are very, very wrong in this case, but I would not say that it could never be translated as you suggest."

I see nothing "interesting" in the fact that I am posting anonymously. I do NOT express "my" opinions, I am interpreting the exact intention of the statement.

"proprement parlé" it's just ordinary French MAID language!

You know the difference between INTERPRETING and TRANSLATING?


Proprement parlé il'ya la differance!

Touche!
I think you are very, very wrong in this case, but I would not say that it could never be translated as you suggest.

Let me put it this way: I am NEVER wrong, I might make an error.

In the contest of the sentence :

""Mise en bon ordre du poste de travail à « proprement parlé » et des équipements."

It means exactly as I said.

To maintain promptly clean station (or place) of work, "in plain language", as well as any and all lab equipment.

It could be also "per se", or "as stated"

Any way WTF?

My bold, her capitals. For the record, there was no sign-off ("Regards", "much love and kisses") either.
Rather amusingly, I think "WTF" is about all there is to say about this incoherent nonsense, although I would personally rather avoid such language in professional communication.
But to get back to the point of posting it - how could you discuss the merits or various terminology choices, say, with someone who claims to be "never wrong"?

* At some point within two days of disagreeing with me, the username changed - to a word spelled wrongly. The profile has a link to a Polish website (proego.co.pl). At the time of disagreeing with me, the google map showing the place of residence of this individual pointed to some state in the American mid-West, I forget which one; 2 days later, it was pointing to Hawaii. If I were of a mind to track her (or him?) down, truly, it would require outstanding sleuthing skills.