So, first for the notion of « vente à la découpe » à la française.
The term is used in fairly formal contexts : http://www.foncia-valorisation.fr/vente-immeubles.html The notion is very evocative and it is easy to understand what is meant. You take a whole and it is sold off in individual units. Here’s a general summary of who, what, where, when and why : http://www.vente-appartement-occupe.com/en/vente-decoupe-ven... It’s common enough a term for Wikipedia to have a succinct entry on the subject : https://fr.wikipedia.org/wiki/Vente_à_la_découpe There are also a fair number of estate agent website which provide explanations as to what it is. Here’s just one which provides a rather lengthy set of explanations covering various situations in which it may arise and what duties and obligations arise : http://www.logic-immo.com/guide-immobilier/bien-acheter/vent...
What is is called in English? Well, the Proz entry already suggests “split sale”. Are there any reliable references for that?

http://www.green-acres.com/en/properties/51926.htm
Possibility of a split sale in two lots:
Le Petit Couvent 380 000 €
The 3 Cottages 460 000 €

http://www.c21selectgroup.com/properties/fallbrook-californi...
31 06 TOTAL ACRES AT THIS WELL MANICURED LAND 3 FULLY LEGALLY SPLIT PARCELS ARE INCLUDED IN THE SALES PRICE APN-108-1003-200 (27 71 ACRES), APN-108-100-32-00 (1 95 ACRES), APN-108-100-34-00 (1 40 ACRES) THERE IS A CLEAR AND GRADED PAD WITH ALL UTILITIES FOR FUTURE CUSTOM HOME SITE HOUSE PLAN HAVE ALREADY BEEN APPROVED AND READY FOR BUILD OUT OTHER HOMES SITES ARE ALSO POSSIBLE ON THE OTHER TWO PARCELS GENTLE TOPOGRAPHY, IN A LOCATION WITH VIEWS OF CITY LIGHTS,PANORAMIC VIEWS OF THE SURROUNDING VALLEY, WITH A YEAR ROUND CREEK THAT FLOWS THROUGH THE LANDSCAPE THE SITE ALSO INCLUDES ALL UTILITIES FROM SEPTIC,WATER,ELECTRIC METER, AND ELECTRIC POLES A GREAT PRICE AND INVESTMENT POTENTIAL FOR 3 FULLY SPLIT PARCELS
© 2015 California Regional Multiple Listing Service, Inc.
Courtesy of Coldwell Banker Res-Vail Ranch.

A FR/EN source with a glossary in FR and in EN:

http://www.cbre.fr/fr_fr/etudes/etudes_lexique which explains the difference between “block sale” (sale of several units to one owner) and the reverse, a “split sale” (sale of several units to several different owners):
- Blocks of premises : Two approaches are used to appraise the market value of blocks of premises, in particular blocks of flats.
o Either the sale of the whole block
o Or the sale unit by unit (flat by flat, split sales)

- Block sale : Sale of an entire multiple occupancy building to the same person or body corporate, bought with the intention of making a profit when the building is sold, often by selling the building in units.
- Co-ownership : A form of ownership in which an entire building or group of buildings is owned by several people. The property is split into several units, each unit having a private area and a share in the common areas. The law of 10/07/1965 and its decree of application of 17/03/1967 instituted a widely mandatory single regime.

- Property agent : Specific to France, a property agent is a broker who buys real estate for his own benefit himself, then sells the property (either in its entirety or split into units) with the aim of making a profit. - See more at: http://www.cbre.fr/fr_fr/etudes/etudes_lexique#sthash.e9jCDl...

http://portal.cbre.eu/portal/page/portal/fr_fr/etudes/etudes...
hhhh
- Immeubles collectifs :
Deux approches de la valeur vénale peuvent être pratiquées pour les immeubles collectifs, en particulier pour le logement :
o soit une vente « en bloc »,
o soit une cession lot par lot (« vente à la découpe »).

- Marchand de biens : Professionnel dont l’activité consiste à acheter des immeubles pour son propre compte et les revendre ensuite en bloc ou à la découpe avec l’intention de réaliser une plus value. -





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Note added at 21 hrs (2015-07-25 01:03:55 GMT)
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"Une vente à la découpe est la transformatoin d'un immeuble en pleine propriété en une copropriété dans le but de procéder à une vente de la totalité de l'immeuble lot par lot."

A split sale is the transformation of a freehold building into a co-ownership/condominium (or whatever term you are using here) with the aim of selling the whole block, unit by unit.

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Note added at 21 hrs (2015-07-25 01:04:43 GMT)
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For "selling" you may prefer "disposing of".

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Note added at 21 hrs (2015-07-25 01:06:49 GMT)
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The terms "en pleine propriété" can also be rendered in a number of ways, depending on how the property in qustion is actually held, not to mention the country where your target reader is based.

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Note added at 21 hrs (2015-07-25 01:33:28 GMT)
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Previous entries in the ProZ glossaries :

http://www.proz.com/kudoz/french_to_english/real_estate/3288...

This one does point out the meaning of "split sale" can have a different meaning (=split commission if 2 parties work on a sale). It does also raise the term "condo conversion" as being useful for the US, which is understood in the UK too, but I argue is accurate for the terms "transformation ... en copropriété" for example, but fails to answer the question of "vente" ; it deals with the definition of the term, not the term itself. It is like saying a condo covnersion is a condo conversion. If the word "sale" does not appear, then you are going to have problems with the rest of your sentence.

The other glossary entry :
http://www.proz.com/kudoz/french_to_english/real_estate/9339...



Have you noticed that your sentence is identical, word for word, to the question psoted in 2009?

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Note added at 1 day2 hrs (2015-07-25 06:43:58 GMT)
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It is essential to go back to the context and see how to make it all fit together.
I am not saying that this is not a condominium conversion here. It obviously describes precisely that so agree that it is a condo conversion here.
What I am saying however, is that in the context of the sentence, the condo conversion appears later in the definition provided in the term "copropriété". The difficulty is avoiding saying a condo is a condo.

"Une vente à la découpe est la transformatoin d'un immeuble en pleine propriété en une copropriété dans le but de procéder à une vente de la totalité de l'immeuble lot par lot."

Does this work?

"A condominium conversion is the conversion of a building in sole ownership into a condominium with the aim of selling the whole block, unit by unit."

Th

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Note added at 1 day2 hrs (2015-07-25 06:52:26 GMT)
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I admit to having misread the "conversion" here does describes the conversion not only of the building itself (if necessary, which is not always the case) , but the conversion of the nature of the ownership.

I knew that a condo invovled multiple ownership.
In my mind "condo covnersion" was limited to the building and not the alternation of the nature of the ownership.

I was also fixing on my British understanding. I'd maintain my suggestion for a British context, but this is Canadian. With careful phrasing - taking care to avoid saying a condo is a condo - of "condo conversion" has the same meaning in Canada, then that is the best solution for the target.

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Note added at 1 day3 hrs (2015-07-25 07:24:02 GMT)
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Candian law of condominium conversion probably vary from province ot province.
Ontario has a Condominium Act dating back to 1998 and there is apparently some change underway at the very moment.
The 1998 Ontario law by way of example : http://www.ontario.ca/laws/statute/98c19

here is a thesis which dsecribes how the term "condo conversion" means not just (or not necessarily) conversion of the building but also the legal change of status.

https://circle.ubc.ca/bitstream/handle/2429/26916/UBC_1987_A...

See page 3, section 1.2., The Condominium Conversion Phenomenon".




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Note added at 1 day3 hrs (2015-07-25 07:27:56 GMT)
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If your target reader is (was, as it's now gone), then my Canadian refs are neither use nor ornament!