Your plans don't matter - the member state where you currently have normal residence does:

Source: https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1430377687650&uri=CELEX:32006L0126

Also, note that a member state where you do not have normal residence can still take measures in order to reduce the validity of your driving licence in its territory further to a violation of the road rules. See case C-260/13, Refusal of a Member State to recognise, in the case of a person having driven under the influence of narcotic substances, the validity of a driving licence issued by another Member State

Your plans don't matter - the member state where you currently have normal residence does:

Source: DIRECTIVE 2006/126/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL

Also, note that a member state where you do not have normal residence can still take measures in order to reduce the validity of your driving licence in its territory further to a violation of the road rules. See case C-260/13, Refusal of a Member State to recognise, in the case of a person having driven under the influence of narcotic substances, the validity of a driving licence issued by another Member State

The thing is, the French state does not want to give me my driving licence back

They are under no obligation to do so; in fact, it's obligatory for you to exchange your driving license when you commit a traffic offense in the country where you live:

Obligatory exchange of your driving licence in another EU country

You have to exchange your driving licence if:

- Your licence is lost, stolen or damaged
- After 2 years of usual residence, if you have a driving licence 
  with an indefinite validity period (only if this is required by 
  the national authorities in the country where you live)
- You commit a traffic offence in the country where you live

Source: Driving licence exchange and recognition in the EU

Since I no longer plan to live in France, am I indeed obliged to change it into a French one?

Your plans don't matter - the member state where you currently have normal residence does:

DIRECTIVE 2006/126/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL
of 20 December 2006 on driving licences (Recast)
  [...]
Article 7
Issue, validity and renewal
1.   Driving licences shall be issued only to those applicants:
  [...]
(e) who have their normal residence in the territory of the Member State
    issuing the licence, or can produce evidence that they have been studying
    there for at least six months.
  [...]
3.   The renewal of driving licences when their administrative validity
     expires shall be subject to:
  [...]
(b) normal residence in the territory of the Member State issuing the licence,
    or evidence that applicants have been studying there for at least six months.

Source: https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1430377687650&uri=CELEX:32006L0126

If you want a driving license right now, you can exchange your Polish driving license with a French one, in accordance with French regulations. Or, you can move your residence to another member state, and exchange your driving license there, with a local one.

Since I no longer plan to live in France, am I indeed obliged to change it into a French one?

Your plans don't matter - the member state where you currently have normal residence does:

DIRECTIVE 2006/126/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL
of 20 December 2006 on driving licences (Recast)
  [...]
Article 7
Issue, validity and renewal
1.   Driving licences shall be issued only to those applicants:
  [...]
(e) who have their normal residence in the territory of the Member State
    issuing the licence, or can produce evidence that they have been studying
    there for at least six months.
  [...]
3.   The renewal of driving licences when their administrative validity
     expires shall be subject to:
  [...]
(b) normal residence in the territory of the Member State issuing the licence,
    or evidence that applicants have been studying there for at least six months.

Source: https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1430377687650&uri=CELEX:32006L0126

If you want a driving license right now, you can exchange your Polish driving license with a French one, in accordance with French regulations. Or, you can move your residence to another member state, and exchange your driving license there, with a local one.

I am essentially asking if France has the right to suspend and then destroy a document given to me by my home country.

Yes. You have acquired normal residence in France; as a consequence , France can suspend or cancel your driving license. Quoting from the same EU directive:

(15) For reasons connected with road safety, Member States should be
     able to apply their national provisions on the withdrawal, 
     suspension, renewal and cancellation of driving licences to all
     licence holders having acquired normal residence in their
     territory.

Also, note that a member state where you do not have normal residence can still take measures in order to reduce the validity of your driving licence in its territory further to a violation of the road rules. See case C-260/13, Refusal of a Member State to recognise, in the case of a person having driven under the influence of narcotic substances, the validity of a driving licence issued by another Member State