French Doors

Without a photo that’s guessing If there is any brickwork or timber structure above doors then yes as doors will sag in the middle then become stuck or can’t shut them

There needs to be a lintel to carry the load of the brickwork above.

Lentil is very important. Only cowboy trade person will encourage installation without lentil.

There must Need a Lintel without Lintel it could work but You wall structure with the passage of time getting unequal settlement and All load will be on The Door So The best is don’t take any risk and put lintel.

If there is a window in place at the moment but no visible lintel, it may have a keystone setup in place, it’s a very rare building detail but it does exist. You’ll likely find the existing window has an angled steel attached - if replaced before and a visible DPC on the underside of the brick work, which would need replacing if the work is done. For piece of mind you could have a builder quote to install a lintel in place as part of the job.