No brakes at all, or marginal brakes?
I believe even your car has at least 2 'channels', meaning the rear brakes should do something even if the front channel goes out.
The smoke makes me suspect that one of the calipers stuck, and overheated, which in turn causes the brake fluid to boil, and the front channel to fail.
Does the pedal offer any resistance now?
Nice car, BTW!
Once had a caliper seize on a 450se. Plenty of smoke.
I was able to limp home with the caliper removed, and that line plugged with big screw and a hose clamp. Worked, but do not try this at home! I'm older and more risk-averse now...
1986 300E 5-Speed 240k mi.