The French bulldog should originally have a short, thick tail, tapering towards the end. - either a straight tail or a tail with a malformed vertebra (hemivertebra) and thus born with a "kinked" or so called screwed tail.

In 1924 when the internationally renowned artist and show judge Vinton P. Breese illustrated commentaries to the breed standard on account of the American breed club you can see on the drawings, that the French bulldog has a strong tail, either straight or shorter screwed - and both varieties cover the anus (rectal opening) with good margin.

This is also shown in the Swedish breed club's illustratd commentaries
of 1996 - se the drawings on pages 1, 16, 19, 20 and 22.
It can be downloaded in pdf-format from the FBKS website.

Unfortunately, during the past few decades - at the same time as ever
shorter backs have been awarded and selected for - there has been
a shortening of the tails of the French Bullldogs:
a short and thick tail has become more and more unusual in the breed.
The tail has become more and more underdeveloped.

NEW OFFICIAL FCI BREED STANDARD FCI-St. No 101/ 09.04.2015 ENGLISH
Quote - important change underlined:
TAIL: Naturally short, ideally long enough to cover the anus, set low, rather straight, thick at the base and tap ering at the tip. A kinked, knotted, broken or relatively long tail that does not reach beyond the point of the hocks, is admitted. It is carried low. Even in action, the tail must not rise above the horizontal.

Quote from the old official F.C.I. Breed Standard:
"TAIL: Short, set low on the rump, close to the buttocks, thick at the base, knotted or kinked naturally and tapering at the tip. Even in action, must stay below the horizontal. A relatively long tail (not reaching beyond the point of the hocks), kinked and tapering is admissible, but not desirable."

"Faults:--- "Tail carried high, or too long or abnormally short." ---
Disqualifications: --- "Taillessness." ---

The tail shall thus be short, thick at the base and tapering towards the tip. An underdeveloped tail, reduced to one or a few vertebrae and not even covering the anus, does not correspond to the requirements in the breed standard. One or a few vertebrae do not form any visible tail broad at the base and narrowing towards the tip - there are possibly a few coat hairs as a sign of reducement and degeneration. In extreme cases - unfortunately not only a few - the tail stump can even be indented into an inch-deep pocket of skin giving severe problems. Cause: the official breed standard has been ignored.

Luckily there are still Frenchies with a correct tail - according to the breed standard, so there is no reason to breed for underdeveloped tails, disqualified in the breed standard:

The breed standard is evidently aware of this tendency towards degenerated tails - and condemns it:
In the F.C.I. official breed standard is stipulated, that taillessness is a disqualifying fault in a French Bulldog. A French bulldog without a tail can consequently not be awarded any prize at a show and a tailless Frenchie may not be used in breeding. Even an abnormally short tail is a fault according to the standard - and should not be given any high award.

A tail too short can cause problems: it can be so close as to develope pressure wounds or eczema under the tail, and it can give hygiene problems at defecation. A Frenchie exposing its rump is not even very pretty! Still in the 1970-ties a tailless Frenchie showing off its anus would have made people wonder.

SHORTENING OF THE SPINE CAUSES SERIOUS MALFORMATIONS:
Anatomically the tail is a natural prolongation of the spine, so it is mere fortune if a malformed "knotted tail" vertebra so to speak is not also formed further up in the back with serious consequences. (Unfortunately, this frequently also happens). Having to to amputate and remove indented tail knuckles is also an expensive and painful surgery to perform. Deformed spine vertebrae is a hereditary, genetic, embryotic developement disturbance:

The shorter the back and tail, the more extreme the degree of malformation
- hemivertebrae and other deformations.

Herniated (open) spine marrow - spina bifida
Spina bifida is most common in English and French Bulldogs. In the USA those breeds contribute to 30 % of the cases according to the SKC Canine Genetic Anomalies Anomalex. The defect can be limited to a small hollow in the spine. In more svere cases there are also disturbed nerve functions in the rear body parts. A puppy can even be born with the spine marrow exposed. This defect is genetically conected to anoura, taillessness and congenital stump tail. Several short-tailed breeds can be affected. The stump tail mutation is caused by failing in a T-box protein binding to DNA.

Read more about various vertebrae defects in the French bulldog back and tail in Dr. Jan Grebe's article Hemivertebrae, also found in the breed club magazine archive at the French Bulldog Club of Sweden website, in a Swedish translation, approved by the author.

Information about the consequences of Show judges' and Breeders' selection for ever shorter spine and tails are found at the French Bulldog Club of America:
Quote: "The spine of a chondrodystrophic breed is also shortened by its abnormal type of development. Although the breed standard calls for a short and compact body, it should not be too short as the standard also calls for good proportion. Frenchies have a high incidence of vertebral malformations, and also of premature degeneration of the intervertebral discs. The shorter the back, the more extreme the degree of malformation of the vertebrae. As the spine is excessively shortened the size of the chest cavity is reduced, which restricts the lung capacity and compromises an already marginal respiratory system.
Excessive shortening can also affect gait, particularly if the dog is so close coupled that its gait is crabbed as it tries to prevent its hind feet overtaking its front feet. Though a Frenchie's movement is not weighted as heavily in the standard as that of many breeds, its movement should be "unrestrained, free and vigorous." If the spine is so short that there is not enough length of neck, the reach of the forelimbs will be reduced, as the neck muscles that move the forelimbs forward will be unable to shorten sufficiently to produce a good forward motion at the shoulder."End quote.
See also: French Bulldog Club of America and more about spine defects at The Boston Terrier Club of America and About The FBDCA French Bulldog Spine Database - read also about cropped tail history and functions by Pilar Hannan.

The French Bulldog is to have a natural tail and has never been one of the docked breeds, when this was allowed. The Frenchie tail is in fact allowed to be fairly long according to the breed standard, assuming it is not carried above the topline - this due to the stipulated roached back - see the pdf-commentaries, pages 16 and 22.

There is every reason for all show judges and breeders to take this unnatural shortening of the Frenchie tail under consideration.

THE SWEDISH KENNEL CLUB has decided that an acronym for tail status
will be added to the registration no. of puppies born after 2007/12/31.
The Swedish Breed Club has applied for an exemption from this registration.

The S.K.C. definitions of tail status is as follows:

1. Total lack of tail (agenes), congenital lack of all the
tail vertebrae is very rare in dogs. This defect is more common
among some cat breeds and is then called the manx-factor.
Animals with tail agenes often have spina bifida (herniated
backbone marrow) and/or serious gait defects moving.

2. Taillessness (anura or anoura) means that the dog has 2-4 tail vertebrae.
- In French anura is called "anoure" and this term is used in the official
F.C.I. breed standard of the country of origin for this disqualifying fault. -

3. Stump tail (brachyura) means that the dog has four to eight vertebrae.

4. Short tail means that the dog has at least eight tail vertebrae, but a shorter
than normal tail (for the breed).

The zoological term for taillessness anura is composed by
the greek negation an = without and oura = tail.
The spelling is either anura or anoura - as used in the French official F.C.I. breed standard
for this disqualifying fault.