First step be to determine if it uses French threading. Given the age and origin it could be English or French threaded. I see a GB stem, so lets hope it's English. Shimano and most other manufacturers no longer support French threading, so it can become problematic to get replacement parts like bottom brackets and headsets. They're out there but generally have to be ordered and can get expensive. French bicycles also use smaller diameter tubing which requires smaller front derailleur clamps (or shimming) smaller diameter seat posts and smaller diameter handlebar stems (or sanding).

Check the threading on the fixed (drive side) bottom bracket cup. An English cup will be left hand threaded while a French cup will have right hand threads.

Beyond that, all vintage frames will have some compatibility issues. The biggest is probably the rear hub width. It's 120mm or most boom era models, but 130mm or most modern bicycles. You'll have to spread the frame's rear trangle and realign the dropouts.

The other common problem is brake mounting. Most modern brakesets use shorter mounting bolts with recessed nuts, so you often have to drill mounting holes and obtain longer collar nuts. A lot of modern brakes may not have the necessary reach to the rims, especially if you also convert to the smaller, more common 700C wheels.

While the problems are not unsurmountable you will spend a lot of time and money, especially if the threading turns out to be French.