The exhaust pipe is quite close too, and when heating tube isn't installed it is easy to have wiring to touch the hot pipe. And, don't get surprised of any issues you have on your 2CV, it is over 30-40 years old whatever the paperwork says. Also about originality of your car, as what you have writed about and photos, it is clearly on other identity, and when that occurs no-one can say what like for example the wirings should be...

https://www.tesa.com/industry/tesa-51608.html
A
I have used this tape on wiring looms, it is the same that automotive industry uses, on Europe, can't say what they use on States...

Original tape on wiring was without glue, and they had sticky tape only on the ends of loom. Now saying that was on 70-90 2CV:s. The tape was like electrical tape you can find even on supermarkets, but without any glue on it...

Sounds like self amalgamating tape to me!

I've never seen self amalgamating tape (which is butyl based) used on original car wiring looms. It is used for waterproofing connections in outside locations such as antenna and LNBs on satellite dishes. it has a slightly tacky feel which would make it difficult to feed through holes and grommets and It is relatively expensive. It is also bulkier than the original.

The original loom wrapping is a plain PVC tape which is smooth and stretchy and has been said before is finished at each end by a traditional cloth insulating tape.

A suggestion..

Using these items and make your own loom parts, robust, waterproof also comes apart easily etc will outlast the car

Wiring....
http://www.vehicle-wiring-products.eu/s ... wall-cable


Sleeving....
http://www.vehicle-wiring-products.eu/p ... c-sleeving



Connectors....
http://www.vehicle-wiring-products.eu/s ... connectors

The self amalgamating tape I have used is thinner than the sticky stuff, and not especially expensive - though they appear to vary greatly:
https://www.ebay.co.uk/sch/items/?_nkw= ... rmvSB=true