That’s the title of a radio or a TV program, starting at 12PM and ending at 2PM.

As we commonly use 24 hour based time, that’s 12 heures – 14 heures

Here are various examples of this usage:

https://www.station-millenium.com/radio/les-emissions/le-12-14/

http://www.galaxieradio.fr/emissions/le-12-14-avec-guillaume-25

https://www.liberation.fr/medias/2000/10/02/naissance-du-12-14-sur-france-3_339231

Using an hour as a substantive is very common in this context. Both main French TV channels evening news have been called le 20 heures for decades.
– TF1
– Antenne 2/France 2

Similarily, the midday news is called le 13 heures.

There is an ellipsis in these expressions, the whole sentence being le journal de 20 heures.

When the span of the TV program is used instead of the starting hour, a slash is used:

NRJ 6/9
France 3 19/20 and 12/13

Unlike with the expression un cinq à sept, the preposition à is never used when referring to TV or radio programs like le 12/14 except with the sept à huit. One might notice both forms with an à are using the more informal 12 hour clock while the ones without it are using a 24 hour clock.

As an answer already asserts it is a radio program. There might be in the title they’ve chosen a bit of an innocuous word play if we remenber what used to be called “le 5 à 7” in France at a not too distant time in the past and which is still being called so, although the term seems to enjoy less publicity nowadays; the definition due to Wikipedia is faithful to what I think I know of this social habit such as developped in France : the 5 à 7 is renowned for that particular kind of activity that consists in rejoining lovers so as to spend with them a part of the day that, avowedly, would last from 5 to 7 o’clock in the afternoon.

Here is what wikipedia justly says;

Cinq à sept originally referred to a time for a tryst, and consequently a metonymy for visit to one’s mistress, an affair, and the mistress (or lover) involved. It derived from the time of day French men would make such a visit. It is still commonly considered today as the moment of the day to meet one’s mistress or lover, and the term is understood with a sexual content (as opposed to Quebec habit).

To make a long story short:

le douze quatorze est une émission qui passe entre midi et deux.