I certainly need one in my appartment but it is for me to arrange.  I do not recall ever having a control 'forced' on me and I have been in the appartment 20 years.  I would suggest

1. you check with the regie who normally be the organisation to authorise this

2. You check with neighbours as it does not make sense that only one appartment is controlled

3. You call the government organisation using the excuse that you thought it was this week but can they confirm.  If they do not know what you are talking about.....!!! If they do they can tell you how long it will take

4. If you are not sure, demand identity although I would n ot know what an identity card would look like

5. Be wary of letting more than one person in

6. They should be able to tell you what day

As yopu can see from the above the short answer is that I do not know

I fully agree with Paul’s comments.  Normally, if there’s any “checking” to be done, you will receive written notification from the régie, the landlord, the owner – in other words, the office/person to whom you pay the rent, so why not telephone him/her to inquire whether the inspection is genuine.  If it is not, the régie (or whoever) will be grateful for your input because it suggests that there are people who are casing the property.

My advice is not to let anyone in without advance written confirmation that the “check” is indeed authentic.

If you get another telephone call from the “controller” ask for his name, address and telephone number “just in case I need to contact you”.  That may bring the story to a close.  However, report the incident to the régie anyway to let him know what’s going on.

Take good care and all the best, R.

I had received a letter from my Regie informing of this event which I just didn't pay any attention to.  The person from the department of Controle Electrique showed up.   He basically looked at the fuse box (tableau Electrique).  Went around the entire apartment and connected his meter to every power outlet and measure the current.  Then he was done.  10 minutes in total.

No harm done :)

A Controllle for a Electrical installation was obligatory every 20 years in Switzerland, each appartement need to check by a company aproved by the "Services industrielles de Genève"

 The safety of electrical installations is governed by a law "Federal Ordinance on Low Voltage Electrical Installations (OIBT)" this law describe the roles and responsibilities of all actors:

The responsibility for the electrical installation is the responsibility of your owner.
However, for your safety:
You are obliged to report any defects to your landlord and to ensure that they are repaired.
If you want to modify or renovate an electrical installation, you must first obtain the written consent of the owner.

Your duties as owner (or owner's representative)
You are responsible for your electrical installations (Art. 5 OIBT). Make sure to:
Keep the technical documentation (diagrams, drawings, safety reports) of your electrical installation,
Have your installations checked by an authorized company (who is not your installer),
Have any defects repaired without delay by an authorized company.

And i agree with what Paul E has written, sometimes we need : to not trust in the first comer

Cheers