Are you planning on replacing just the lower part of the existing headset, or the whole thing? If the latter, you may run into problems.

I'd recommend trying the upper adjustable cup on the existing fork's threads very carefully before installing anything - or getting and using a thread pitch gauge on the threaded portion of the steerer. If it seems to start but binds quickly, you may have an issue with using the Tange upper headset.

According to Sheldon's headset dimension cribsheet (I linked it in my earlier post), there's a chance that you may have a French headset with a 27.0mm crown race (apparently French headsets were made with both 26.5mm and 27.0mm crown races). If so, the fork may be metric thread (25.0mm x 1mm) vice 1" x 24 TPI. JIS upper headset threading is 1" x 24TPI.

Per the same cribsheet, most French steerers have a flat instead of a groove for a keyed washer. However, I don't know if that's universally true - or just almost always true. I'd still test either way, preferably with a thread pitch gauge.

If it turns out you have a French headset with a 27.0mm crown race, you can still use the Tange lower if the lower cup fits your existing head tube tightly enough. But I don't think you'll be able to use the upper part if your steerer is French threaded without replacing the fork.

Edited to Add: Since it appears your Atlantique is from the 1990s, I guess it's possible it used an Asian-made, JIS-spec fork vice one made in France to French specifications (lots of European firms were apparently outsourcing frame work to Asia during that era). If so, it may have been originally built with a JIS headset vice a French headset. Hopefully that turns out to be the case.