Glossary entry (derived from question below)
French term
variante
Variantes
Aucune variante obligatoire ni facultative n’est prévue et le dépôt de variantes libres n’est pas autorisé.
| 4 | variant |
Alison MacG
|
| 4 +1 | variant solution |
Conor McAuley
|
| 4 | variant(s) |
Rosa Paredes
|
| 4 | Variant bid |
juventud
|
| 3 | variation |
kashew
|
Non-PRO (1): cc in nyc
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Proposed translations
United Kingdom
Patents and related material specialist
Native in: English (Variants: Scottish, UK, British) 
Works in: German to English, French to English, Swedish to English, and 4 more.
variant
The terms "variant" and "option" seem to be used as standard in tenders originating from a variety of different countries - even if the precise definitions of what they cover may vary.
I'll reproduce here the links I posted in the discussion section:
II.1.9)Variants will be accepted
Yes
II.2.2)Options
No
http://ted.europa.eu/udl?uri=TED:NOTICE:260383-2011:TEXT:EN:...
a variant is a "technical solution proposed by the tenderer which is different from the specific description of the good to be delivered or the service to be rendered included in the contract documentation as described by its technical specifications"
"options are qualitative (or quantitative) extras ancillary to the service that is the subject of the procurement (something additional to the main subject of the contract which nevertheless is priced and the contracting authority may, in the course of implementation of the contract, decide to buy it)"
http://www.ombudsman.europa.eu/en/cases/draftrecommendation....
The following additional link shows usage in Ireland:
6. Number of Tenders, Mandatory Options and Variants
6.1 Terminology
An option is a Tender required under section 6.2 below.
A variant tender is a Tender complying with section 6.3 below and identified as a variant tender.
A standard tender is a Tender that is not a variant tender.
6.2 Mandatory options
If the Particulars state that any mandatory options are required, the Candidate must submit a separate Tender for each option stated in the Particulars.
6.3 Variant tenders
Unless otherwise stated in the Particulars, variant tenders are not permitted.
If the Particulars state that any variant tenders are permitted, a variant tender must comply with the minimum requirements set out in the Particulars
If so stated in the Particulars, variant tenders may be submitted only by a Candidate who also submits a standard tender.
If not so stated, variant tenders may be submitted without submitting a standard tender.
http://www.galway.ie/en/Services/Housing/PercolationworksKil...
Canada
Criminal, Civil and Immigration Law
Native in: English 
, Spanish (Variants: Latin American, Chilean, Standard-Spain, Mexican)
Works in: Spanish to English, English to Spanish, French to English, and 3 more.
variant(s)
www.cleanvehicle.eu/fileadmin/.../UK/uksi_20060005_en.pdfSh... Format: PDF/Adobe Acrobat
by P PROCUREMENT
9. Technical specifications in the contract documents. 10. Variants. PART 3. PROCEDURES ... (1) These Regulations may be cited as the Public Contracts Regulations 2006 and come into force on .... United Kingdom and includes the Treasury; ...
ETC.
France
Excellence, Expertise & Experience
Native in: English (Variants: Scottish, Irish, British, Wales / Welsh, UK)
Works in: French to English, English
variant solution
I would imagine it refers to a solution which varies from the technical particulars set out in the call for tenders document.
But I think Alison is right -- or at least if that's the language employed in EU docs, you should use that.
Discussion
E.g.:
II.1.9)Variants will be accepted
Yes
II.2.2)Options
No
http://ted.europa.eu/udl?uri=TED:NOTICE:260383-2011:TEXT:EN:...
They are indeed separate terms, although confusing. See this European Ombudsman recommendation in which the Commission was asked to clarify the meaning of the terms.
a variant is a "technical solution proposed by the tenderer which is different from the specific description of the good to be delivered or the service to be rendered included in the contract documentation as described by its technical specifications"
"options are qualitative (or quantitative) extras ancillary to the service that is the subject of the procurement (something additional to the main subject of the contract which nevertheless is priced and the contracting authority may, in the course of implementation of the contract, decide to buy it)"
http://www.ombudsman.europa.eu/en/cases/draftrecommendation....