French dental fricatives

[Particles the Greek]

How would you characterise the sounds which native speakers of French produce when trying to say [ð] and [θ]? They're not quite [z] and [s].

[ol bofosh]

Perhaps [s̪ z̪]?

Looking at Wikipedia it says:

Fricatives: French has three pairs of homorganic fricatives distinguished by voicing, i.e., labiodental /f/~/v/, dental /s/~/z/, and palato-alveolar /ʃ/~/ʒ/. Notice that /s/~/z/ are dental, like the plosives /t/~/d/ and the nasal /n/.

So their /s/ and /z/ are dental, anyway. When I speak French I tend to dentalise them too, instead of using my own native /s/.

[KathTheDragon]

One of the guys from my school had the surname Southy, and one of the French teachers had a really strong French accent, so whenever she said his name, it always sounded like 'Suzzie'.

[vtardif]

fwiw in Québec French they're unmistakeably [d] and [t].